| 1 | //===--- TwineLocalCheck.cpp - clang-tidy ---------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "TwineLocalCheck.h" |
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| 10 | #include "clang/AST/ASTContext.h" |
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| 11 | #include "clang/ASTMatchers/ASTMatchers.h" |
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| 12 | #include "clang/Lex/Lexer.h" |
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| 13 | |
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| 14 | using namespace clang::ast_matchers; |
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| 15 | |
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| 16 | namespace clang::tidy::llvm_check { |
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| 17 | |
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| 18 | void TwineLocalCheck::registerMatchers(MatchFinder *Finder) { |
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| 19 | auto TwineType = |
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| 20 | qualType(hasDeclaration(InnerMatcher: cxxRecordDecl(hasName(Name: "::llvm::Twine" )))); |
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| 21 | Finder->addMatcher( |
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| 22 | NodeMatch: varDecl(unless(parmVarDecl()), hasType(InnerMatcher: TwineType)).bind(ID: "variable" ), |
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| 23 | Action: this); |
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| 24 | } |
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| 25 | |
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| 26 | void TwineLocalCheck::check(const MatchFinder::MatchResult &Result) { |
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| 27 | const auto *VD = Result.Nodes.getNodeAs<VarDecl>(ID: "variable" ); |
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| 28 | auto Diag = diag(VD->getLocation(), |
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| 29 | "twine variables are prone to use-after-free bugs" ); |
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| 30 | |
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| 31 | // If this VarDecl has an initializer try to fix it. |
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| 32 | if (VD->hasInit()) { |
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| 33 | // Peel away implicit constructors and casts so we can see the actual type |
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| 34 | // of the initializer. |
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| 35 | const Expr *C = VD->getInit()->IgnoreImplicit(); |
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| 36 | |
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| 37 | while (isa<CXXConstructExpr>(Val: C)) { |
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| 38 | if (cast<CXXConstructExpr>(Val: C)->getNumArgs() == 0) |
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| 39 | break; |
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| 40 | C = cast<CXXConstructExpr>(Val: C)->getArg(Arg: 0)->IgnoreParenImpCasts(); |
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| 41 | } |
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| 42 | |
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| 43 | SourceRange TypeRange = |
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| 44 | VD->getTypeSourceInfo()->getTypeLoc().getSourceRange(); |
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| 45 | |
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| 46 | // A real Twine, turn it into a std::string. |
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| 47 | if (VD->getType()->getCanonicalTypeUnqualified() == |
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| 48 | C->getType()->getCanonicalTypeUnqualified()) { |
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| 49 | SourceLocation EndLoc = Lexer::getLocForEndOfToken( |
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| 50 | Loc: VD->getInit()->getEndLoc(), Offset: 0, SM: *Result.SourceManager, LangOpts: getLangOpts()); |
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| 51 | Diag << FixItHint::CreateReplacement(RemoveRange: TypeRange, Code: "std::string" ) |
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| 52 | << FixItHint::CreateInsertion(InsertionLoc: VD->getInit()->getBeginLoc(), Code: "(" ) |
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| 53 | << FixItHint::CreateInsertion(InsertionLoc: EndLoc, Code: ").str()" ); |
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| 54 | } else { |
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| 55 | // Just an implicit conversion. Insert the real type. |
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| 56 | Diag << FixItHint::CreateReplacement( |
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| 57 | RemoveRange: TypeRange, |
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| 58 | Code: C->getType().getAsString(Policy: Result.Context->getPrintingPolicy())); |
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| 59 | } |
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| 60 | } |
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| 61 | } |
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| 62 | |
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| 63 | } // namespace clang::tidy::llvm_check |
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| 64 | |
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