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Гапон А.К. 381806-3 #47

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Гапон А.К. 381806-3 #47

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a8e8d7f
Complete c-style-cast-checker task
Andrey0948 May 25, 2021
9d3931b
fix
Andrey0948 May 27, 2021
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25 changes: 19 additions & 6 deletions main.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,13 +18,26 @@ using namespace clang::ast_matchers;
using namespace clang::tooling;

class CastCallBack : public MatchFinder::MatchCallback {
Rewriter& rwr;
public:
CastCallBack(Rewriter& rewriter) {
// Your code goes here
};
CastCallBack(Rewriter& rewriter) : rwr(rewriter) {};

void run(const MatchFinder::MatchResult &Result) override {
// Your code goes here
const auto *expr = Result.Nodes.getNodeAs<CStyleCastExpr>("cast");
if (expr != nullptr) {
auto loc = CharSourceRange::getCharRange(expr->getLParenLoc(),
expr->getSubExprAsWritten()->getBeginLoc());
auto tSource = Lexer::getSourceText(CharSourceRange::getTokenRange(
expr->getLParenLoc().getLocWithOffset(1),
expr->getRParenLoc().getLocWithOffset(-1)), *Result.SourceManager,
Result.Context->getLangOpts());
auto res = ("static_cast<" + tSource + ">(").str();
rwr.ReplaceText(loc, res);
auto closePL = Lexer::getLocForEndOfToken(
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Please describe why you are using Lexer::getLocForEndOfToken(expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc(),...) here.
What would be the difference if expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc().getLocOffset(1) was used as closePL?

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Lexer::getLocForEndOfToken определяет локацию за последним элементом токена

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What is the difference in the use with expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc().getLocOffset(1)?

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Ну эта функция возвращает изначальное местоположение, сразу за концом токена, на который ссылается переданное местоположение expr-> getSubExprAsWritten () -> IgnoreImpCasts () -> getEndLoc ()

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What happens if we use expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc().getLocOffset(1) instead of Lexer::getLocForEndOfToken()?
When does the approach with expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc().getLocOffset(1) not work?

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SubExpr->getEndLoc().getLocWithOffset(1) захватил бы только первый символ имени, в отличие от реализованного варианта.

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@eshulankina

expr->getSubExprAsWritten()->IgnoreImpCasts()->getEndLoc(), 0,
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Please describe what getSubExprAsWritten() does.
What is the difference with getSubExpr() method?

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Получает подвыражение приведения как написано в исходном коде, просматривая неявные приведения или другие промежуточные узлы, которые были добавлены семантическим анализом.
getSubExpr возвращает итоговый результат, с учетом неявных приведений и промежуточных узлов

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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:
image

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

*Result.SourceManager, Result.Context->getLangOpts());
rwr.InsertText(closePL, ")");
}
}
};

Expand All @@ -47,7 +60,7 @@ class MyASTConsumer : public ASTConsumer {
class CStyleCheckerFrontendAction : public ASTFrontendAction {
public:
CStyleCheckerFrontendAction() = default;

void EndSourceFileAction() override {
rewriter_.getEditBuffer(rewriter_.getSourceMgr().getMainFileID())
.write(llvm::outs());
Expand All @@ -65,7 +78,7 @@ class CStyleCheckerFrontendAction : public ASTFrontendAction {
static llvm::cl::OptionCategory CastMatcherCategory("cast-matcher options");

int main(int argc, const char **argv) {
auto Parser = llvm::ExitOnError()(CommonOptionsParser::create(argc, argv, CastMatcherCategory));
CommonOptionsParser Parser(argc, argv, CastMatcherCategory);

ClangTool Tool(Parser.getCompilations(), Parser.getSourcePathList());
return Tool.run(newFrontendActionFactory<CStyleCheckerFrontendAction>().get());
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