clang-tools  14.0.0git
VirtualClassDestructorCheck.cpp
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1 //===--- VirtualClassDestructorCheck.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 
10 #include "../utils/LexerUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 #include <string>
15 
16 using namespace clang::ast_matchers;
17 
18 namespace clang {
19 namespace tidy {
20 namespace cppcoreguidelines {
21 
22 AST_MATCHER(CXXRecordDecl, hasPublicVirtualOrProtectedNonVirtualDestructor) {
23  // We need to call Node.getDestructor() instead of matching a
24  // CXXDestructorDecl. Otherwise, tests will fail for class templates, since
25  // the primary template (not the specialization) always gets a non-virtual
26  // CXXDestructorDecl in the AST. https://bugs.llvm.org/show_bug.cgi?id=51912
27  const CXXDestructorDecl *Destructor = Node.getDestructor();
28  if (!Destructor)
29  return false;
30 
31  return (((Destructor->getAccess() == AccessSpecifier::AS_public) &&
32  Destructor->isVirtual()) ||
33  ((Destructor->getAccess() == AccessSpecifier::AS_protected) &&
34  !Destructor->isVirtual()));
35 }
36 
37 void VirtualClassDestructorCheck::registerMatchers(MatchFinder *Finder) {
38  ast_matchers::internal::Matcher<CXXRecordDecl> InheritsVirtualMethod =
39  hasAnyBase(hasType(cxxRecordDecl(has(cxxMethodDecl(isVirtual())))));
40 
41  Finder->addMatcher(
42  cxxRecordDecl(
43  anyOf(has(cxxMethodDecl(isVirtual())), InheritsVirtualMethod),
44  unless(hasPublicVirtualOrProtectedNonVirtualDestructor()))
45  .bind("ProblematicClassOrStruct"),
46  this);
47 }
48 
49 static CharSourceRange
50 getVirtualKeywordRange(const CXXDestructorDecl &Destructor,
51  const SourceManager &SM, const LangOptions &LangOpts) {
52  SourceLocation VirtualBeginLoc = Destructor.getBeginLoc();
53  SourceLocation VirtualEndLoc = VirtualBeginLoc.getLocWithOffset(
54  Lexer::MeasureTokenLength(VirtualBeginLoc, SM, LangOpts));
55 
56  /// Range ends with \c StartOfNextToken so that any whitespace after \c
57  /// virtual is included.
58  SourceLocation StartOfNextToken =
59  Lexer::findNextToken(VirtualEndLoc, SM, LangOpts)
60  .getValue()
61  .getLocation();
62 
63  return CharSourceRange::getCharRange(VirtualBeginLoc, StartOfNextToken);
64 }
65 
66 static const AccessSpecDecl *
67 getPublicASDecl(const CXXRecordDecl &StructOrClass) {
68  for (DeclContext::specific_decl_iterator<AccessSpecDecl>
69  AS{StructOrClass.decls_begin()},
70  ASEnd{StructOrClass.decls_end()};
71  AS != ASEnd; ++AS) {
72  AccessSpecDecl *ASDecl = *AS;
73  if (ASDecl->getAccess() == AccessSpecifier::AS_public)
74  return ASDecl;
75  }
76 
77  return nullptr;
78 }
79 
80 static FixItHint
81 generateUserDeclaredDestructor(const CXXRecordDecl &StructOrClass,
82  const SourceManager &SourceManager) {
83  std::string DestructorString;
84  SourceLocation Loc;
85  bool AppendLineBreak = false;
86 
87  const AccessSpecDecl *AccessSpecDecl = getPublicASDecl(StructOrClass);
88 
89  if (!AccessSpecDecl) {
90  if (StructOrClass.isClass()) {
91  Loc = StructOrClass.getEndLoc();
92  DestructorString = "public:";
93  AppendLineBreak = true;
94  } else {
95  Loc = StructOrClass.getBraceRange().getBegin().getLocWithOffset(1);
96  }
97  } else {
98  Loc = AccessSpecDecl->getEndLoc().getLocWithOffset(1);
99  }
100 
101  DestructorString = (llvm::Twine(DestructorString) + "\nvirtual ~" +
102  StructOrClass.getName().str() + "() = default;" +
103  (AppendLineBreak ? "\n" : ""))
104  .str();
105 
106  return FixItHint::CreateInsertion(Loc, DestructorString);
107 }
108 
109 static std::string getSourceText(const CXXDestructorDecl &Destructor) {
110  std::string SourceText;
111  llvm::raw_string_ostream DestructorStream(SourceText);
112  Destructor.print(DestructorStream);
113  return SourceText;
114 }
115 
116 static std::string eraseKeyword(std::string &DestructorString,
117  const std::string &Keyword) {
118  size_t KeywordIndex = DestructorString.find(Keyword);
119  if (KeywordIndex != std::string::npos)
120  DestructorString.erase(KeywordIndex, Keyword.length());
121  return DestructorString;
122 }
123 
125  const std::string &Visibility, const CXXDestructorDecl &Destructor,
126  const SourceManager &SM, const LangOptions &LangOpts) {
127  std::string DestructorString =
128  (llvm::Twine() + Visibility + ":\n" +
129  (Visibility == "public" && !Destructor.isVirtual() ? "virtual " : ""))
130  .str();
131 
132  std::string OriginalDestructor = getSourceText(Destructor);
133  if (Visibility == "protected" && Destructor.isVirtualAsWritten())
134  OriginalDestructor = eraseKeyword(OriginalDestructor, "virtual ");
135 
136  DestructorString =
137  (llvm::Twine(DestructorString) + OriginalDestructor +
138  (Destructor.isExplicitlyDefaulted() ? ";\n" : "") + "private:")
139  .str();
140 
141  /// Semicolons ending an explicitly defaulted destructor have to be deleted.
142  /// Otherwise, the left-over semicolon trails the \c private: access
143  /// specifier.
144  SourceLocation EndLocation;
145  if (Destructor.isExplicitlyDefaulted())
146  EndLocation =
147  utils::lexer::findNextTerminator(Destructor.getEndLoc(), SM, LangOpts)
148  .getLocWithOffset(1);
149  else
150  EndLocation = Destructor.getEndLoc().getLocWithOffset(1);
151 
152  auto OriginalDestructorRange =
153  CharSourceRange::getCharRange(Destructor.getBeginLoc(), EndLocation);
154  return FixItHint::CreateReplacement(OriginalDestructorRange,
155  DestructorString);
156 }
157 
159  const MatchFinder::MatchResult &Result) {
160 
161  const auto *MatchedClassOrStruct =
162  Result.Nodes.getNodeAs<CXXRecordDecl>("ProblematicClassOrStruct");
163 
164  const CXXDestructorDecl *Destructor = MatchedClassOrStruct->getDestructor();
165  if (!Destructor)
166  return;
167 
168  if (Destructor->getAccess() == AccessSpecifier::AS_private) {
169  diag(MatchedClassOrStruct->getLocation(),
170  "destructor of %0 is private and prevents using the type")
171  << MatchedClassOrStruct;
172  diag(MatchedClassOrStruct->getLocation(),
173  /*FixDescription=*/"make it public and virtual", DiagnosticIDs::Note)
175  "public", *Destructor, *Result.SourceManager, getLangOpts());
176  diag(MatchedClassOrStruct->getLocation(),
177  /*FixDescription=*/"make it protected", DiagnosticIDs::Note)
179  "protected", *Destructor, *Result.SourceManager, getLangOpts());
180 
181  return;
182  }
183 
184  // Implicit destructors are public and non-virtual for classes and structs.
185  bool ProtectedAndVirtual = false;
186  FixItHint Fix;
187 
188  if (MatchedClassOrStruct->hasUserDeclaredDestructor()) {
189  if (Destructor->getAccess() == AccessSpecifier::AS_public) {
190  Fix = FixItHint::CreateInsertion(Destructor->getLocation(), "virtual ");
191  } else if (Destructor->getAccess() == AccessSpecifier::AS_protected) {
192  ProtectedAndVirtual = true;
193  Fix = FixItHint::CreateRemoval(getVirtualKeywordRange(
194  *Destructor, *Result.SourceManager, Result.Context->getLangOpts()));
195  }
196  } else {
197  Fix = generateUserDeclaredDestructor(*MatchedClassOrStruct,
198  *Result.SourceManager);
199  }
200 
201  diag(MatchedClassOrStruct->getLocation(),
202  "destructor of %0 is %select{public and non-virtual|protected and "
203  "virtual}1")
204  << MatchedClassOrStruct << ProtectedAndVirtual;
205  diag(MatchedClassOrStruct->getLocation(),
206  "make it %select{public and virtual|protected and non-virtual}0",
207  DiagnosticIDs::Note)
208  << ProtectedAndVirtual << Fix;
209 }
210 
211 } // namespace cppcoreguidelines
212 } // namespace tidy
213 } // namespace clang
Loc
SourceLocation Loc
Definition: KernelNameRestrictionCheck.cpp:45
clang::tidy::cppcoreguidelines::getPublicASDecl
static const AccessSpecDecl * getPublicASDecl(const CXXRecordDecl &StructOrClass)
Definition: VirtualClassDestructorCheck.cpp:67
clang::tidy::cppcoreguidelines::getSourceText
static std::string getSourceText(const CXXDestructorDecl &Destructor)
Definition: VirtualClassDestructorCheck.cpp:109
Fix
static cl::opt< bool > Fix("fix", cl::desc(R"( Apply suggested fixes. Without -fix-errors clang-tidy will bail out if any compilation errors were found. )"), cl::init(false), cl::cat(ClangTidyCategory))
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::cppcoreguidelines::eraseKeyword
static std::string eraseKeyword(std::string &DestructorString, const std::string &Keyword)
Definition: VirtualClassDestructorCheck.cpp:116
clang::ast_matchers::AST_MATCHER
AST_MATCHER(Expr, isMacroID)
Definition: PreferIsaOrDynCastInConditionalsCheck.cpp:19
clang::clangd::check
bool check(llvm::StringRef File, llvm::function_ref< bool(const Position &)> ShouldCheckLine, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:253
VirtualClassDestructorCheck.h
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::utils::lexer::findNextTerminator
SourceLocation findNextTerminator(SourceLocation Start, const SourceManager &SM, const LangOptions &LangOpts)
Definition: LexerUtils.cpp:75
clang::tidy::cppcoreguidelines::generateUserDeclaredDestructor
static FixItHint generateUserDeclaredDestructor(const CXXRecordDecl &StructOrClass, const SourceManager &SourceManager)
Definition: VirtualClassDestructorCheck.cpp:81
SM
const SourceManager & SM
Definition: IncludeCleaner.cpp:108
clang::tidy::cppcoreguidelines::changePrivateDestructorVisibilityTo
static FixItHint changePrivateDestructorVisibilityTo(const std::string &Visibility, const CXXDestructorDecl &Destructor, const SourceManager &SM, const LangOptions &LangOpts)
Definition: VirtualClassDestructorCheck.cpp:124
clang::tidy::cppcoreguidelines::getVirtualKeywordRange
static CharSourceRange getVirtualKeywordRange(const CXXDestructorDecl &Destructor, const SourceManager &SM, const LangOptions &LangOpts)
Definition: VirtualClassDestructorCheck.cpp:50