Чистов В.М. 381806-2 #52
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| virtual void run(const MatchFinder::MatchResult &Result) { | ||
| if (const auto *CastT = Result.Nodes.getNodeAs<CStyleCastExpr>("cast")) { | ||
| if (CastT->getExprLoc().isMacroID()) |
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What does this check mean? Please describe examples of when this check returns true and when this check returns false.
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Проверяем является ли выражение макросом. Если не является, то приведение типов в нем игнорируется
| if (CastT->getExprLoc().isMacroID()) | ||
| return; | ||
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| if (CastT->getCastKind() == CK_ToVoid) |
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What does this check mean? Please describe examples of when this check returns true and when this check returns false.
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Проверка на наличие типа void перед переменной. Такая ((void)<var_name>) конструкция используется, чтобы указать неиспользуемые переменные, что предотвратит появление предупреждений от компилятора. Возвращает true, если выражение имеет вид (void)<var_name>, false, если в скобках указан другой тип
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| const auto* CastIgn = CastT->getSubExprAsWritten()->IgnoreImpCasts(); | ||
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| if (!isa<ParenExpr>(CastIgn)) { |
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What does this check mean? Please describe examples of when this check returns true and when this check returns false.
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Проверка на наличие скобок у выражения. Если их нет, то они добавляются, если есть, то ничего не происходит
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| std::string TextT(("static_cast<" + StringT + ">").str()); | ||
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| const auto* CastIgn = CastT->getSubExprAsWritten()->IgnoreImpCasts(); |
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Please describe the reason why you are using IgnoreImpCasts() here.
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IgnoreImpCasts() игнорирует неявные приведения типов, но в данном примере функция необязательна для использования
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If you try to print the AST of the test.cpp example, you will see that you have several ImplicitCastExpr nodes:
Depending on which approaches you use to get the subexpression node, you will get different result nodes for the test.cpp example:
Code:
// getSubExpr() retrieves the first cast subexpression
llvm::outs() << "getSubExpr(): " << castNode->getSubExpr()->getStmtClassName();
// getSubExprAsWritten() retrieves the cast subexpression as it was written in the source
// code, looking through any implicit casts or other intermediate nodes
// introduced by semantic analysis.
llvm::outs() << "getSubExprAsWritten(): " << castNode->getSubExprAsWritten()->getStmtClassName();
// getSubExpr() retrieves the first cast subexpression.
// ignoreImpCasts() skips past any implicit casts which might surround this expression until
// reaching a fixed point. It skips the following AST nodes: ImplicitCastExpr, FullExpr.
llvm::outs() << "getSubExpr()->ignoreImpCasts(): " << castNode->getSubExpr()->IgnoreImpCasts()->getStmtClassName();Output:
getSubExpr(): ImplicitCastExpr
getSubExprAsWritten(): DeclRefExpr
getSubExpr()->ignoreImpCasts(): DeclRefExpr
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