clang-tools  15.0.0git
TwineLocalCheck.cpp
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1 //===--- TwineLocalCheck.cpp - clang-tidy ---------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "TwineLocalCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchers.h"
12 #include "clang/Lex/Lexer.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace llvm_check {
19 
20 void TwineLocalCheck::registerMatchers(MatchFinder *Finder) {
21  auto TwineType =
22  qualType(hasDeclaration(cxxRecordDecl(hasName("::llvm::Twine"))));
23  Finder->addMatcher(
24  varDecl(unless(parmVarDecl()), hasType(TwineType)).bind("variable"),
25  this);
26 }
27 
28 void TwineLocalCheck::check(const MatchFinder::MatchResult &Result) {
29  const auto *VD = Result.Nodes.getNodeAs<VarDecl>("variable");
30  auto Diag = diag(VD->getLocation(),
31  "twine variables are prone to use-after-free bugs");
32 
33  // If this VarDecl has an initializer try to fix it.
34  if (VD->hasInit()) {
35  // Peel away implicit constructors and casts so we can see the actual type
36  // of the initializer.
37  const Expr *C = VD->getInit()->IgnoreImplicit();
38 
39  while (isa<CXXConstructExpr>(C)) {
40  if (cast<CXXConstructExpr>(C)->getNumArgs() == 0)
41  break;
42  C = cast<CXXConstructExpr>(C)->getArg(0)->IgnoreParenImpCasts();
43  }
44 
45  SourceRange TypeRange =
46  VD->getTypeSourceInfo()->getTypeLoc().getSourceRange();
47 
48  // A real Twine, turn it into a std::string.
49  if (VD->getType()->getCanonicalTypeUnqualified() ==
50  C->getType()->getCanonicalTypeUnqualified()) {
51  SourceLocation EndLoc = Lexer::getLocForEndOfToken(
52  VD->getInit()->getEndLoc(), 0, *Result.SourceManager, getLangOpts());
53  Diag << FixItHint::CreateReplacement(TypeRange, "std::string")
54  << FixItHint::CreateInsertion(VD->getInit()->getBeginLoc(), "(")
55  << FixItHint::CreateInsertion(EndLoc, ").str()");
56  } else {
57  // Just an implicit conversion. Insert the real type.
58  Diag << FixItHint::CreateReplacement(
59  TypeRange,
60  C->getType().getAsString(Result.Context->getPrintingPolicy()));
61  }
62  }
63 }
64 
65 } // namespace llvm_check
66 } // namespace tidy
67 } // namespace clang
clang::clangd::check
bool check(llvm::StringRef File, llvm::Optional< Range > LineRange, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:273
clang::ast_matchers
Definition: AbseilMatcher.h:14
TwineLocalCheck.h
C
const Criteria C
Definition: FunctionCognitiveComplexityCheck.cpp:93
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27