C++ QualType::getNonReferenceType方法代码示例

static CallExpr *create_call_once_funcptr_call(ASTContext &C, ASTMaker M,
                                               const ParmVarDecl *Callback,
                                               ArrayRef<Expr *> CallArgs) {

  QualType Ty = Callback->getType();
  DeclRefExpr *Call = M.makeDeclRefExpr(Callback);
  Expr *SubExpr;
  if (Ty->isRValueReferenceType()) {
    SubExpr = M.makeImplicitCast(
        Call, Ty.getNonReferenceType(), CK_LValueToRValue);
  } else if (Ty->isLValueReferenceType() &&
             Call->getType()->isFunctionType()) {
    Ty = C.getPointerType(Ty.getNonReferenceType());
    SubExpr = M.makeImplicitCast(Call, Ty, CK_FunctionToPointerDecay);
  } else if (Ty->isLValueReferenceType()
             && Call->getType()->isPointerType()
             && Call->getType()->getPointeeType()->isFunctionType()){
    SubExpr = Call;
  } else {
    llvm_unreachable("Unexpected state");
  }

  return CallExpr::Create(C, SubExpr, CallArgs, C.VoidTy, VK_RValue,
                          SourceLocation());
}

bool pointedTypesAreEqual(QualType SourceType, QualType DestType) {
  SourceType = SourceType.getNonReferenceType();
  DestType = DestType.getNonReferenceType();
  while (SourceType->isPointerType() && DestType->isPointerType()) {
    SourceType = SourceType->getPointeeType();
    DestType = DestType->getPointeeType();
  }
  return SourceType.getUnqualifiedType() == DestType.getUnqualifiedType();
}

bool needsConstCast(QualType SourceType, QualType DestType) {
  SourceType = SourceType.getNonReferenceType();
  DestType = DestType.getNonReferenceType();
  while (SourceType->isPointerType() && DestType->isPointerType()) {
    SourceType = SourceType->getPointeeType();
    DestType = DestType->getPointeeType();
    if (SourceType.isConstQualified() && !DestType.isConstQualified())
      return true;
  }
  return false;
}

/// ActOnCXXNamedCast - Parse {dynamic,static,reinterpret,const}_cast's.
Action::OwningExprResult
Sema::ActOnCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
                        SourceLocation LAngleBracketLoc, TypeTy *Ty,
                        SourceLocation RAngleBracketLoc,
                        SourceLocation LParenLoc, ExprArg E,
                        SourceLocation RParenLoc) {
  Expr *Ex = E.takeAs<Expr>();
  // FIXME: Preserve type source info.
  QualType DestType = GetTypeFromParser(Ty);
  SourceRange OpRange(OpLoc, RParenLoc);
  SourceRange DestRange(LAngleBracketLoc, RAngleBracketLoc);

  // If the type is dependent, we won't do the semantic analysis now.
  // FIXME: should we check this in a more fine-grained manner?
  bool TypeDependent = DestType->isDependentType() || Ex->isTypeDependent();

  switch (Kind) {
  default: assert(0 && "Unknown C++ cast!");

  case tok::kw_const_cast:
    if (!TypeDependent)
      CheckConstCast(*this, Ex, DestType, OpRange, DestRange);
    return Owned(new (Context) CXXConstCastExpr(DestType.getNonReferenceType(),
                                                Ex, DestType, OpLoc));

  case tok::kw_dynamic_cast: {
    CastExpr::CastKind Kind = CastExpr::CK_Unknown;
    if (!TypeDependent)
      CheckDynamicCast(*this, Ex, DestType, OpRange, DestRange, Kind);
    return Owned(new (Context)CXXDynamicCastExpr(DestType.getNonReferenceType(),
                                                 Kind, Ex, DestType, OpLoc));
  }
  case tok::kw_reinterpret_cast:
    if (!TypeDependent)
      CheckReinterpretCast(*this, Ex, DestType, OpRange, DestRange);
    return Owned(new (Context) CXXReinterpretCastExpr(
                                  DestType.getNonReferenceType(),
                                  Ex, DestType, OpLoc));

  case tok::kw_static_cast: {
    CastExpr::CastKind Kind = CastExpr::CK_Unknown;
    if (!TypeDependent)
      CheckStaticCast(*this, Ex, DestType, OpRange, Kind);
    return Owned(new (Context) CXXStaticCastExpr(DestType.getNonReferenceType(),
                                                 Kind, Ex, DestType, OpLoc));
  }
  }

  return ExprError();
}

long long clang_Type_getSizeOf(CXType T) {
  if (T.kind == CXType_Invalid)
    return CXTypeLayoutError_Invalid;
  ASTContext &Ctx = cxtu::getASTUnit(GetTU(T))->getASTContext();
  QualType QT = GetQualType(T);
  // [expr.sizeof] p2: if reference type, return size of referenced type
  if (QT->isReferenceType())
    QT = QT.getNonReferenceType();
  // [expr.sizeof] p1: return -1 on: func, incomplete, bitfield, incomplete
  //                   enumeration
  // Note: We get the cxtype, not the cxcursor, so we can't call
  //       FieldDecl->isBitField()
  // [expr.sizeof] p3: pointer ok, function not ok.
  // [gcc extension] lib/AST/ExprConstant.cpp:1372 HandleSizeof : vla == error
  if (QT->isIncompleteType())
    return CXTypeLayoutError_Incomplete;
  if (QT->isDependentType())
    return CXTypeLayoutError_Dependent;
  if (!QT->isConstantSizeType())
    return CXTypeLayoutError_NotConstantSize;
  // [gcc extension] lib/AST/ExprConstant.cpp:1372
  //                 HandleSizeof : {voidtype,functype} == 1
  // not handled by ASTContext.cpp:1313 getTypeInfoImpl
  if (QT->isVoidType() || QT->isFunctionType())
    return 1;
  return Ctx.getTypeSizeInChars(QT).getQuantity();
}

/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType using the pre-computed implicit
/// conversion sequence ICS. Returns true if there was an error, false
/// otherwise. The expression From is replaced with the converted
/// expression. Flavor is the kind of conversion we're performing,
/// used in the error message.
bool
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
                                const ImplicitConversionSequence &ICS,
                                const char* Flavor) {
  switch (ICS.ConversionKind) {
  case ImplicitConversionSequence::StandardConversion:
    if (PerformImplicitConversion(From, ToType, ICS.Standard, Flavor))
      return true;
    break;

  case ImplicitConversionSequence::UserDefinedConversion:
    // FIXME: This is, of course, wrong. We'll need to actually call
    // the constructor or conversion operator, and then cope with the
    // standard conversions.
    ImpCastExprToType(From, ToType.getNonReferenceType(), 
                      ToType->isLValueReferenceType());
    return false;

  case ImplicitConversionSequence::EllipsisConversion:
    assert(false && "Cannot perform an ellipsis conversion");
    return false;

  case ImplicitConversionSequence::BadConversion:
    return true;
  }

  // Everything went well.
  return false;
}

/// Model calls to AssertionResult constructors that are not inlined.
void GTestChecker::checkPostCall(const CallEvent &Call,
                                 CheckerContext &C) const {
  /// If the constructor was inlined, there is no need model it.
  if (C.wasInlined)
    return;

  initIdentifierInfo(C.getASTContext());

  auto *CtorCall = dyn_cast<CXXConstructorCall>(&Call);
  if (!CtorCall)
    return;

  const CXXConstructorDecl *CtorDecl = CtorCall->getDecl();
  const CXXRecordDecl *CtorParent = CtorDecl->getParent();
  if (CtorParent->getIdentifier() != AssertionResultII)
    return;

  if (CtorDecl->getNumParams() == 0)
    return;


  // Call the appropriate modeling method based on the type of the first
  // constructor parameter.
  const ParmVarDecl *ParamDecl = CtorDecl->getParamDecl(0);
  QualType ParamType = ParamDecl->getType();
  if (CtorDecl->getNumParams() <= 2 &&
      ParamType.getNonReferenceType()->getCanonicalTypeUnqualified() ==
      C.getASTContext().BoolTy) {
    // The first parameter is either a boolean or reference to a boolean
    modelAssertionResultBoolConstructor(CtorCall, C);

  } else if (CtorDecl->isCopyConstructor()) {
    modelAssertionResultCopyConstructor(CtorCall, C);
  }
}

static CallExpr *create_call_once_funcptr_call(ASTContext &C, ASTMaker M,
                                               const ParmVarDecl *Callback,
                                               ArrayRef<Expr *> CallArgs) {

  QualType Ty = Callback->getType();
  DeclRefExpr *Call = M.makeDeclRefExpr(Callback);
  CastKind CK;
  if (Ty->isRValueReferenceType()) {
    CK = CK_LValueToRValue;
  } else {
    assert(Ty->isLValueReferenceType());
    CK = CK_FunctionToPointerDecay;
    Ty = C.getPointerType(Ty.getNonReferenceType());
  }

  return new (C)
      CallExpr(C, M.makeImplicitCast(Call, Ty.getNonReferenceType(), CK),
               /*args=*/CallArgs,
               /*QualType=*/C.VoidTy,
               /*ExprValueType=*/VK_RValue,
               /*SourceLocation=*/SourceLocation());
}

CXXUnresolvedConstructExpr::CXXUnresolvedConstructExpr(
                                                 SourceLocation TyBeginLoc,
                                                 QualType T,
                                                 SourceLocation LParenLoc,
                                                 Expr **Args,
                                                 unsigned NumArgs,
                                                 SourceLocation RParenLoc)
  : Expr(CXXUnresolvedConstructExprClass, T.getNonReferenceType(),
         T->isDependentType(), true),
    TyBeginLoc(TyBeginLoc),
    Type(T),
    LParenLoc(LParenLoc),
    RParenLoc(RParenLoc),
    NumArgs(NumArgs) {
  Stmt **StoredArgs = reinterpret_cast<Stmt **>(this + 1);
  memcpy(StoredArgs, Args, sizeof(Expr *) * NumArgs);
}

long long clang_Type_getAlignOf(CXType T) {
  if (T.kind == CXType_Invalid)
    return CXTypeLayoutError_Invalid;
  ASTContext &Ctx = cxtu::getASTUnit(GetTU(T))->getASTContext();
  QualType QT = GetQualType(T);
  // [expr.alignof] p1: return size_t value for complete object type, reference
  //                    or array.
  // [expr.alignof] p3: if reference type, return size of referenced type
  if (QT->isReferenceType())
    QT = QT.getNonReferenceType();
  if (QT->isIncompleteType())
    return CXTypeLayoutError_Incomplete;
  if (QT->isDependentType())
    return CXTypeLayoutError_Dependent;
  // Exceptions by GCC extension - see ASTContext.cpp:1313 getTypeInfoImpl
  // if (QT->isFunctionType()) return 4; // Bug #15511 - should be 1
  // if (QT->isVoidType()) return 1;
  return Ctx.getTypeAlignInChars(QT).getQuantity();
}

void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
  const auto *CastExpr = Result.Nodes.getNodeAs<CStyleCastExpr>("cast");

  // Ignore casts in macros.
  if (CastExpr->getExprLoc().isMacroID())
    return;

  // Casting to void is an idiomatic way to mute "unused variable" and similar
  // warnings.
  if (CastExpr->getCastKind() == CK_ToVoid)
    return;

  auto isFunction = [](QualType T) {
    T = T.getCanonicalType().getNonReferenceType();
    return T->isFunctionType() || T->isFunctionPointerType() ||
           T->isMemberFunctionPointerType();
  };

  const QualType DestTypeAsWritten =
      CastExpr->getTypeAsWritten().getUnqualifiedType();
  const QualType SourceTypeAsWritten =
      CastExpr->getSubExprAsWritten()->getType().getUnqualifiedType();
  const QualType SourceType = SourceTypeAsWritten.getCanonicalType();
  const QualType DestType = DestTypeAsWritten.getCanonicalType();

  auto ReplaceRange = CharSourceRange::getCharRange(
      CastExpr->getLParenLoc(), CastExpr->getSubExprAsWritten()->getBeginLoc());

  bool FnToFnCast =
      isFunction(SourceTypeAsWritten) && isFunction(DestTypeAsWritten);

  if (CastExpr->getCastKind() == CK_NoOp && !FnToFnCast) {
    // Function pointer/reference casts may be needed to resolve ambiguities in
    // case of overloaded functions, so detection of redundant casts is trickier
    // in this case. Don't emit "redundant cast" warnings for function
    // pointer/reference types.
    if (SourceTypeAsWritten == DestTypeAsWritten) {
      diag(CastExpr->getBeginLoc(), "redundant cast to the same type")
          << FixItHint::CreateRemoval(ReplaceRange);
      return;
    }
  }

  // The rest of this check is only relevant to C++.
  // We also disable it for Objective-C++.
  if (!getLangOpts().CPlusPlus || getLangOpts().ObjC1 || getLangOpts().ObjC2)
    return;
  // Ignore code inside extern "C" {} blocks.
  if (!match(expr(hasAncestor(linkageSpecDecl())), *CastExpr, *Result.Context)
           .empty())
    return;
  // Ignore code in .c files and headers included from them, even if they are
  // compiled as C++.
  if (getCurrentMainFile().endswith(".c"))
    return;

  SourceManager &SM = *Result.SourceManager;

  // Ignore code in .c files #included in other files (which shouldn't be done,
  // but people still do this for test and other purposes).
  if (SM.getFilename(SM.getSpellingLoc(CastExpr->getBeginLoc())).endswith(".c"))
    return;

  // Leave type spelling exactly as it was (unlike
  // getTypeAsWritten().getAsString() which would spell enum types 'enum X').
  StringRef DestTypeString =
      Lexer::getSourceText(CharSourceRange::getTokenRange(
                               CastExpr->getLParenLoc().getLocWithOffset(1),
                               CastExpr->getRParenLoc().getLocWithOffset(-1)),
                           SM, getLangOpts());

  auto Diag =
      diag(CastExpr->getBeginLoc(), "C-style casts are discouraged; use %0");

  auto ReplaceWithCast = [&](std::string CastText) {
    const Expr *SubExpr = CastExpr->getSubExprAsWritten()->IgnoreImpCasts();
    if (!isa<ParenExpr>(SubExpr)) {
      CastText.push_back('(');
      Diag << FixItHint::CreateInsertion(
          Lexer::getLocForEndOfToken(SubExpr->getEndLoc(), 0, SM,
                                     getLangOpts()),
          ")");
    }
    Diag << FixItHint::CreateReplacement(ReplaceRange, CastText);
  };
  auto ReplaceWithNamedCast = [&](StringRef CastType) {
    Diag << CastType;
    ReplaceWithCast((CastType + "<" + DestTypeString + ">").str());
  };

  // Suggest appropriate C++ cast. See [expr.cast] for cast notation semantics.
  switch (CastExpr->getCastKind()) {
  case CK_FunctionToPointerDecay:
    ReplaceWithNamedCast("static_cast");
    return;
  case CK_ConstructorConversion:
    if (!CastExpr->getTypeAsWritten().hasQualifiers() &&
        DestTypeAsWritten->isRecordType() &&
        !DestTypeAsWritten->isElaboratedTypeSpecifier()) {
      Diag << "constructor call syntax";
//.........这里部分代码省略.........

OMPClause *Sema::ActOnOpenMPFirstprivateClause(ArrayRef<Expr *> VarList,
                                               SourceLocation StartLoc,
                                               SourceLocation LParenLoc,
                                               SourceLocation EndLoc) {
  SmallVector<Expr *, 8> Vars;
  for (ArrayRef<Expr *>::iterator I = VarList.begin(), E = VarList.end();
       I != E; ++I) {
    assert(*I && "NULL expr in OpenMP firstprivate clause.");
    if (isa<DependentScopeDeclRefExpr>(*I)) {
      // It will be analyzed later.
      Vars.push_back(*I);
      continue;
    }

    SourceLocation ELoc = (*I)->getExprLoc();
    // OpenMP [2.1, C/C++]
    //  A list item is a variable name.
    // OpenMP  [2.9.3.3, Restrictions, p.1]
    //  A variable that is part of another variable (as an array or
    //  structure element) cannot appear in a private clause.
    DeclRefExpr *DE = dyn_cast_or_null<DeclRefExpr>(*I);
    if (!DE || !isa<VarDecl>(DE->getDecl())) {
      Diag(ELoc, diag::err_omp_expected_var_name)
        << (*I)->getSourceRange();
      continue;
    }
    Decl *D = DE->getDecl();
    VarDecl *VD = cast<VarDecl>(D);

    QualType Type = VD->getType();
    if (Type->isDependentType() || Type->isInstantiationDependentType()) {
      // It will be analyzed later.
      Vars.push_back(DE);
      continue;
    }

    // OpenMP [2.9.3.3, Restrictions, C/C++, p.3]
    //  A variable that appears in a private clause must not have an incomplete
    //  type or a reference type.
    if (RequireCompleteType(ELoc, Type,
                            diag::err_omp_firstprivate_incomplete_type)) {
      continue;
    }
    if (Type->isReferenceType()) {
      Diag(ELoc, diag::err_omp_clause_ref_type_arg)
        << getOpenMPClauseName(OMPC_firstprivate) << Type;
      bool IsDecl = VD->isThisDeclarationADefinition(Context) ==
                    VarDecl::DeclarationOnly;
      Diag(VD->getLocation(), IsDecl ? diag::note_previous_decl :
                                       diag::note_defined_here) << VD;
      continue;
    }

    // OpenMP [2.9.3.4, Restrictions, C/C++, p.1]
    //  A variable of class type (or array thereof) that appears in a private
    //  clause requires an accesible, unambiguous copy constructor for the
    //  class type.
    Type = Context.getBaseElementType(Type);
    CXXRecordDecl *RD = getLangOpts().CPlusPlus ?
                          Type.getNonReferenceType()->getAsCXXRecordDecl() : 0;
    if (RD) {
      CXXConstructorDecl *CD = LookupCopyingConstructor(RD, 0);
      PartialDiagnostic PD =
        PartialDiagnostic(PartialDiagnostic::NullDiagnostic());
      if (!CD ||
          CheckConstructorAccess(ELoc, CD,
                                 InitializedEntity::InitializeTemporary(Type),
                                 CD->getAccess(), PD) == AR_inaccessible ||
          CD->isDeleted()) {
        Diag(ELoc, diag::err_omp_required_method)
             << getOpenMPClauseName(OMPC_firstprivate) << 1;
        bool IsDecl = VD->isThisDeclarationADefinition(Context) ==
                      VarDecl::DeclarationOnly;
        Diag(VD->getLocation(), IsDecl ? diag::note_previous_decl :
                                         diag::note_defined_here) << VD;
        Diag(RD->getLocation(), diag::note_previous_decl) << RD;
        continue;
      }
      MarkFunctionReferenced(ELoc, CD);
      DiagnoseUseOfDecl(CD, ELoc);

      CXXDestructorDecl *DD = RD->getDestructor();
      if (DD) {
        if (CheckDestructorAccess(ELoc, DD, PD) == AR_inaccessible ||
            DD->isDeleted()) {
          Diag(ELoc, diag::err_omp_required_method)
               << getOpenMPClauseName(OMPC_firstprivate) << 4;
          bool IsDecl = VD->isThisDeclarationADefinition(Context) ==
                        VarDecl::DeclarationOnly;
          Diag(VD->getLocation(), IsDecl ? diag::note_previous_decl :
                                           diag::note_defined_here) << VD;
          Diag(RD->getLocation(), diag::note_previous_decl) << RD;
          continue;
        }
        MarkFunctionReferenced(ELoc, DD);
        DiagnoseUseOfDecl(DD, ELoc);
      }
    }

    // If StartLoc and EndLoc are invalid - this is an implicit firstprivate
//.........这里部分代码省略.........

DSAStackTy::DSAVarData DSAStackTy::getTopDSA(VarDecl *D) {
  DSAVarData DVar;

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  //  Variables appearing in threadprivate directives are threadprivate.
  if (D->getTLSKind() != VarDecl::TLS_None) {
    DVar.CKind = OMPC_threadprivate;
    return DVar;
  }
  if (Stack[0].SharingMap.count(D)) {
    DVar.RefExpr = Stack[0].SharingMap[D].RefExpr;
    DVar.CKind = OMPC_threadprivate;
    return DVar;
  }

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.1]
  // Variables with automatic storage duration that are declared in a scope
  // inside the construct are private.
  OpenMPDirectiveKind Kind = getCurrentDirective();
  if (Kind != OMPD_parallel) {
    if (isOpenMPLocal(D, llvm::next(Stack.rbegin())) && D->isLocalVarDecl() &&
        (D->getStorageClass() == SC_Auto ||
         D->getStorageClass() == SC_None))
      DVar.CKind = OMPC_private;
      return DVar;
  }

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.4]
  //  Static data memebers are shared.
  if (D->isStaticDataMember()) {
    // Variables with const-qualified type having no mutable member may be listed
    // in a firstprivate clause, even if they are static data members.
    DSAVarData DVarTemp = hasDSA(D, OMPC_firstprivate);
    if (DVarTemp.CKind == OMPC_firstprivate && DVarTemp.RefExpr)
      return DVar;

    DVar.CKind = OMPC_shared;
    return DVar;
  }

  QualType Type = D->getType().getNonReferenceType().getCanonicalType();
  bool IsConstant = Type.isConstant(Actions.getASTContext());
  while (Type->isArrayType()) {
    QualType ElemType = cast<ArrayType>(Type.getTypePtr())->getElementType();
    Type = ElemType.getNonReferenceType().getCanonicalType();
  }
  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.6]
  //  Variables with const qualified type having no mutable member are
  //  shared.
  CXXRecordDecl *RD = Actions.getLangOpts().CPlusPlus ?
                                Type->getAsCXXRecordDecl() : 0;
  if (IsConstant &&
      !(Actions.getLangOpts().CPlusPlus && RD && RD->hasMutableFields())) {
    // Variables with const-qualified type having no mutable member may be
    // listed in a firstprivate clause, even if they are static data members.
    DSAVarData DVarTemp = hasDSA(D, OMPC_firstprivate);
    if (DVarTemp.CKind == OMPC_firstprivate && DVarTemp.RefExpr)
      return DVar;

    DVar.CKind = OMPC_shared;
    return DVar;
  }

  // OpenMP [2.9.1.1, Data-sharing Attribute Rules for Variables Referenced
  // in a Construct, C/C++, predetermined, p.7]
  //  Variables with static storage duration that are declared in a scope
  //  inside the construct are shared.
  if (D->isStaticLocal()) {
    DVar.CKind = OMPC_shared;
    return DVar;
  }

  // Explicitly specified attributes and local variables with predetermined
  // attributes.
  if (Stack.back().SharingMap.count(D)) {
    DVar.RefExpr = Stack.back().SharingMap[D].RefExpr;
    DVar.CKind = Stack.back().SharingMap[D].Attributes;
  }

  return DVar;
}

/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType by following the standard
/// conversion sequence SCS. Returns true if there was an error, false
/// otherwise. The expression From is replaced with the converted
/// expression. Flavor is the context in which we're performing this
/// conversion, for use in error messages.
bool 
Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
                                const StandardConversionSequence& SCS,
                                const char *Flavor) {
  // Overall FIXME: we are recomputing too many types here and doing
  // far too much extra work. What this means is that we need to keep
  // track of more information that is computed when we try the
  // implicit conversion initially, so that we don't need to recompute
  // anything here.
  QualType FromType = From->getType();

  if (SCS.CopyConstructor) {
    // FIXME: Create a temporary object by calling the copy
    // constructor.
    ImpCastExprToType(From, ToType.getNonReferenceType(), 
                      ToType->isLValueReferenceType());
    return false;
  }

  // Perform the first implicit conversion.
  switch (SCS.First) {
  case ICK_Identity:
  case ICK_Lvalue_To_Rvalue:
    // Nothing to do.
    break;

  case ICK_Array_To_Pointer:
    FromType = Context.getArrayDecayedType(FromType);
    ImpCastExprToType(From, FromType);
    break;

  case ICK_Function_To_Pointer:
    if (Context.getCanonicalType(FromType) == Context.OverloadTy) {
      FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType, true);
      if (!Fn)
        return true;

      if (DiagnoseUseOfDecl(Fn, From->getSourceRange().getBegin()))
        return true;

      FixOverloadedFunctionReference(From, Fn);
      FromType = From->getType();
    }
    FromType = Context.getPointerType(FromType);
    ImpCastExprToType(From, FromType);
    break;

  default:
    assert(false && "Improper first standard conversion");
    break;
  }

  // Perform the second implicit conversion
  switch (SCS.Second) {
  case ICK_Identity:
    // Nothing to do.
    break;

  case ICK_Integral_Promotion:
  case ICK_Floating_Promotion:
  case ICK_Complex_Promotion:
  case ICK_Integral_Conversion:
  case ICK_Floating_Conversion:
  case ICK_Complex_Conversion:
  case ICK_Floating_Integral:
  case ICK_Complex_Real:
  case ICK_Compatible_Conversion:
      // FIXME: Go deeper to get the unqualified type!
    FromType = ToType.getUnqualifiedType();
    ImpCastExprToType(From, FromType);
    break;

  case ICK_Pointer_Conversion:
    if (SCS.IncompatibleObjC) {
      // Diagnose incompatible Objective-C conversions
      Diag(From->getSourceRange().getBegin(), 
           diag::ext_typecheck_convert_incompatible_pointer)
        << From->getType() << ToType << Flavor
        << From->getSourceRange();
    }

    if (CheckPointerConversion(From, ToType))
      return true;
    ImpCastExprToType(From, ToType);
    break;

  case ICK_Pointer_Member:
    if (CheckMemberPointerConversion(From, ToType))
      return true;
    ImpCastExprToType(From, ToType);
    break;

  case ICK_Boolean_Conversion:
    FromType = Context.BoolTy;
//.........这里部分代码省略.........

/// ActOnCXXTypeConstructExpr - Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
Action::OwningExprResult
Sema::ActOnCXXTypeConstructExpr(SourceRange TypeRange, TypeTy *TypeRep,
                                SourceLocation LParenLoc,
                                MultiExprArg exprs,
                                SourceLocation *CommaLocs,
                                SourceLocation RParenLoc) {
  assert(TypeRep && "Missing type!");
  QualType Ty = QualType::getFromOpaquePtr(TypeRep);
  unsigned NumExprs = exprs.size();
  Expr **Exprs = (Expr**)exprs.get();
  SourceLocation TyBeginLoc = TypeRange.getBegin();
  SourceRange FullRange = SourceRange(TyBeginLoc, RParenLoc);

  if (Ty->isDependentType() ||
      CallExpr::hasAnyTypeDependentArguments(Exprs, NumExprs)) {
    exprs.release();
    return Owned(new (Context) CXXTemporaryObjectExpr(0, Ty, TyBeginLoc,
                                                      Exprs, NumExprs,
                                                      RParenLoc));
  }


  // C++ [expr.type.conv]p1:
  // If the expression list is a single expression, the type conversion
  // expression is equivalent (in definedness, and if defined in meaning) to the
  // corresponding cast expression.
  //
  if (NumExprs == 1) {
    if (CheckCastTypes(TypeRange, Ty, Exprs[0]))
      return ExprError();
    exprs.release();
    return Owned(new (Context) CXXFunctionalCastExpr(Ty.getNonReferenceType(),
                                                     Ty, TyBeginLoc, Exprs[0],
                                                     RParenLoc));
  }

  if (const RecordType *RT = Ty->getAsRecordType()) {
    CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());

    if (NumExprs > 1 || Record->hasUserDeclaredConstructor()) {
      CXXConstructorDecl *Constructor
        = PerformInitializationByConstructor(Ty, Exprs, NumExprs,
                                             TypeRange.getBegin(),
                                             SourceRange(TypeRange.getBegin(),
                                                         RParenLoc),
                                             DeclarationName(),
                                             IK_Direct);

      if (!Constructor)
        return ExprError();

      exprs.release();
      return Owned(new (Context) CXXTemporaryObjectExpr(Constructor, Ty,
                                                        TyBeginLoc,  Exprs,
                                                        NumExprs, RParenLoc));
    }

    // Fall through to value-initialize an object of class type that
    // doesn't have a user-declared default constructor.
  }

  // C++ [expr.type.conv]p1:
  // If the expression list specifies more than a single value, the type shall
  // be a class with a suitably declared constructor.
  //
  if (NumExprs > 1)
    return ExprError(Diag(CommaLocs[0],
                          diag::err_builtin_func_cast_more_than_one_arg)
      << FullRange);

  assert(NumExprs == 0 && "Expected 0 expressions");

  // C++ [expr.type.conv]p2:
  // The expression T(), where T is a simple-type-specifier for a non-array
  // complete object type or the (possibly cv-qualified) void type, creates an
  // rvalue of the specified type, which is value-initialized.
  //
  if (Ty->isArrayType())
    return ExprError(Diag(TyBeginLoc,
                          diag::err_value_init_for_array_type) << FullRange);
  if (!Ty->isDependentType() && !Ty->isVoidType() &&
      RequireCompleteType(TyBeginLoc, Ty,
                          diag::err_invalid_incomplete_type_use, FullRange))
    return ExprError();

  if (RequireNonAbstractType(TyBeginLoc, Ty,
                             diag::err_allocation_of_abstract_type))
    return ExprError();
  
  exprs.release();
  return Owned(new (Context) CXXZeroInitValueExpr(Ty, TyBeginLoc, RParenLoc));
}