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//===--- TwineLocalCheck.cpp - clang-tidy ---------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "TwineLocalCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace llvm_check {
void TwineLocalCheck::registerMatchers(MatchFinder *Finder) {
auto TwineType =
qualType(hasDeclaration(cxxRecordDecl(hasName("::llvm::Twine"))));
Finder->addMatcher(
varDecl(unless(parmVarDecl()), hasType(TwineType)).bind("variable"),
this);
}
void TwineLocalCheck::check(const MatchFinder::MatchResult &Result) {
const auto *VD = Result.Nodes.getNodeAs<VarDecl>("variable");
auto Diag = diag(VD->getLocation(),
"twine variables are prone to use-after-free bugs");
// If this VarDecl has an initializer try to fix it.
if (VD->hasInit()) {
// Peel away implicit constructors and casts so we can see the actual type
// of the initializer.
const Expr *C = VD->getInit()->IgnoreImplicit();
while (isa<CXXConstructExpr>(C)) {
if (cast<CXXConstructExpr>(C)->getNumArgs() == 0)
break;
C = cast<CXXConstructExpr>(C)->getArg(0)->IgnoreParenImpCasts();
}
SourceRange TypeRange =
VD->getTypeSourceInfo()->getTypeLoc().getSourceRange();
// A real Twine, turn it into a std::string.
if (VD->getType()->getCanonicalTypeUnqualified() ==
C->getType()->getCanonicalTypeUnqualified()) {
SourceLocation EndLoc = Lexer::getLocForEndOfToken(
VD->getInit()->getEndLoc(), 0, *Result.SourceManager, getLangOpts());
Diag << FixItHint::CreateReplacement(TypeRange, "std::string")
<< FixItHint::CreateInsertion(VD->getInit()->getBeginLoc(), "(")
<< FixItHint::CreateInsertion(EndLoc, ").str()");
} else {
// Just an implicit conversion. Insert the real type.
Diag << FixItHint::CreateReplacement(
TypeRange,
C->getType().getAsString(Result.Context->getPrintingPolicy()));
}
}
}
} // namespace llvm_check
} // namespace tidy
} // namespace clang
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