clang-tools  15.0.0git
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 Optional<CharSourceRange>
50 getVirtualKeywordRange(const CXXDestructorDecl &Destructor,
51  const SourceManager &SM, const LangOptions &LangOpts) {
52  if (Destructor.getLocation().isMacroID())
53  return None;
54 
55  SourceLocation VirtualBeginLoc = Destructor.getBeginLoc();
56  SourceLocation VirtualEndLoc = VirtualBeginLoc.getLocWithOffset(
57  Lexer::MeasureTokenLength(VirtualBeginLoc, SM, LangOpts));
58 
59  /// Range ends with \c StartOfNextToken so that any whitespace after \c
60  /// virtual is included.
61  SourceLocation StartOfNextToken =
62  Lexer::findNextToken(VirtualEndLoc, SM, LangOpts)
63  .getValue()
64  .getLocation();
65 
66  return CharSourceRange::getCharRange(VirtualBeginLoc, StartOfNextToken);
67 }
68 
69 static const AccessSpecDecl *
70 getPublicASDecl(const CXXRecordDecl &StructOrClass) {
71  for (DeclContext::specific_decl_iterator<AccessSpecDecl>
72  AS{StructOrClass.decls_begin()},
73  ASEnd{StructOrClass.decls_end()};
74  AS != ASEnd; ++AS) {
75  AccessSpecDecl *ASDecl = *AS;
76  if (ASDecl->getAccess() == AccessSpecifier::AS_public)
77  return ASDecl;
78  }
79 
80  return nullptr;
81 }
82 
83 static FixItHint
84 generateUserDeclaredDestructor(const CXXRecordDecl &StructOrClass,
85  const SourceManager &SourceManager) {
86  std::string DestructorString;
87  SourceLocation Loc;
88  bool AppendLineBreak = false;
89 
90  const AccessSpecDecl *AccessSpecDecl = getPublicASDecl(StructOrClass);
91 
92  if (!AccessSpecDecl) {
93  if (StructOrClass.isClass()) {
94  Loc = StructOrClass.getEndLoc();
95  DestructorString = "public:";
96  AppendLineBreak = true;
97  } else {
98  Loc = StructOrClass.getBraceRange().getBegin().getLocWithOffset(1);
99  }
100  } else {
101  Loc = AccessSpecDecl->getEndLoc().getLocWithOffset(1);
102  }
103 
104  DestructorString = (llvm::Twine(DestructorString) + "\nvirtual ~" +
105  StructOrClass.getName().str() + "() = default;" +
106  (AppendLineBreak ? "\n" : ""))
107  .str();
108 
109  return FixItHint::CreateInsertion(Loc, DestructorString);
110 }
111 
112 static std::string getSourceText(const CXXDestructorDecl &Destructor) {
113  std::string SourceText;
114  llvm::raw_string_ostream DestructorStream(SourceText);
115  Destructor.print(DestructorStream);
116  return SourceText;
117 }
118 
119 static std::string eraseKeyword(std::string &DestructorString,
120  const std::string &Keyword) {
121  size_t KeywordIndex = DestructorString.find(Keyword);
122  if (KeywordIndex != std::string::npos)
123  DestructorString.erase(KeywordIndex, Keyword.length());
124  return DestructorString;
125 }
126 
128  const std::string &Visibility, const CXXDestructorDecl &Destructor,
129  const SourceManager &SM, const LangOptions &LangOpts) {
130  std::string DestructorString =
131  (llvm::Twine() + Visibility + ":\n" +
132  (Visibility == "public" && !Destructor.isVirtual() ? "virtual " : ""))
133  .str();
134 
135  std::string OriginalDestructor = getSourceText(Destructor);
136  if (Visibility == "protected" && Destructor.isVirtualAsWritten())
137  OriginalDestructor = eraseKeyword(OriginalDestructor, "virtual ");
138 
139  DestructorString =
140  (llvm::Twine(DestructorString) + OriginalDestructor +
141  (Destructor.isExplicitlyDefaulted() ? ";\n" : "") + "private:")
142  .str();
143 
144  /// Semicolons ending an explicitly defaulted destructor have to be deleted.
145  /// Otherwise, the left-over semicolon trails the \c private: access
146  /// specifier.
147  SourceLocation EndLocation;
148  if (Destructor.isExplicitlyDefaulted())
149  EndLocation =
150  utils::lexer::findNextTerminator(Destructor.getEndLoc(), SM, LangOpts)
151  .getLocWithOffset(1);
152  else
153  EndLocation = Destructor.getEndLoc().getLocWithOffset(1);
154 
155  auto OriginalDestructorRange =
156  CharSourceRange::getCharRange(Destructor.getBeginLoc(), EndLocation);
157  return FixItHint::CreateReplacement(OriginalDestructorRange,
158  DestructorString);
159 }
160 
162  const MatchFinder::MatchResult &Result) {
163 
164  const auto *MatchedClassOrStruct =
165  Result.Nodes.getNodeAs<CXXRecordDecl>("ProblematicClassOrStruct");
166 
167  const CXXDestructorDecl *Destructor = MatchedClassOrStruct->getDestructor();
168  if (!Destructor)
169  return;
170 
171  if (Destructor->getAccess() == AccessSpecifier::AS_private) {
172  diag(MatchedClassOrStruct->getLocation(),
173  "destructor of %0 is private and prevents using the type")
174  << MatchedClassOrStruct;
175  diag(MatchedClassOrStruct->getLocation(),
176  /*Description=*/"make it public and virtual", DiagnosticIDs::Note)
178  "public", *Destructor, *Result.SourceManager, getLangOpts());
179  diag(MatchedClassOrStruct->getLocation(),
180  /*Description=*/"make it protected", DiagnosticIDs::Note)
182  "protected", *Destructor, *Result.SourceManager, getLangOpts());
183 
184  return;
185  }
186 
187  // Implicit destructors are public and non-virtual for classes and structs.
188  bool ProtectedAndVirtual = false;
189  FixItHint Fix;
190 
191  if (MatchedClassOrStruct->hasUserDeclaredDestructor()) {
192  if (Destructor->getAccess() == AccessSpecifier::AS_public) {
193  Fix = FixItHint::CreateInsertion(Destructor->getLocation(), "virtual ");
194  } else if (Destructor->getAccess() == AccessSpecifier::AS_protected) {
195  ProtectedAndVirtual = true;
196  if (const auto MaybeRange =
197  getVirtualKeywordRange(*Destructor, *Result.SourceManager,
198  Result.Context->getLangOpts()))
199  Fix = FixItHint::CreateRemoval(*MaybeRange);
200  }
201  } else {
202  Fix = generateUserDeclaredDestructor(*MatchedClassOrStruct,
203  *Result.SourceManager);
204  }
205 
206  diag(MatchedClassOrStruct->getLocation(),
207  "destructor of %0 is %select{public and non-virtual|protected and "
208  "virtual}1")
209  << MatchedClassOrStruct << ProtectedAndVirtual;
210  diag(MatchedClassOrStruct->getLocation(),
211  "make it %select{public and virtual|protected and non-virtual}0",
212  DiagnosticIDs::Note)
213  << ProtectedAndVirtual << Fix;
214 }
215 
216 } // namespace cppcoreguidelines
217 } // namespace tidy
218 } // namespace clang
Loc
SourceLocation Loc
Definition: KernelNameRestrictionCheck.cpp:45
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::tidy::cppcoreguidelines::getPublicASDecl
static const AccessSpecDecl * getPublicASDecl(const CXXRecordDecl &StructOrClass)
Definition: VirtualClassDestructorCheck.cpp:70
clang::tidy::cppcoreguidelines::getSourceText
static std::string getSourceText(const CXXDestructorDecl &Destructor)
Definition: VirtualClassDestructorCheck.cpp:112
clang::tidy::cppcoreguidelines::getVirtualKeywordRange
static Optional< CharSourceRange > getVirtualKeywordRange(const CXXDestructorDecl &Destructor, const SourceManager &SM, const LangOptions &LangOpts)
Definition: VirtualClassDestructorCheck.cpp:50
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:119
clang::ast_matchers::AST_MATCHER
AST_MATCHER(Expr, isMacroID)
Definition: PreferIsaOrDynCastInConditionalsCheck.cpp:19
VirtualClassDestructorCheck.h
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
LangOpts
const LangOptions * LangOpts
Definition: ExtractFunction.cpp:366
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:84
clang::tidy::cppcoreguidelines::changePrivateDestructorVisibilityTo
static FixItHint changePrivateDestructorVisibilityTo(const std::string &Visibility, const CXXDestructorDecl &Destructor, const SourceManager &SM, const LangOptions &LangOpts)
Definition: VirtualClassDestructorCheck.cpp:127