clang-tools  14.0.0git
MakeSmartPtrCheck.cpp
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1 //===--- MakeSmartPtrCheck.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 "../utils/TypeTraits.h"
10 #include "MakeSharedCheck.h"
11 #include "clang/Frontend/CompilerInstance.h"
12 #include "clang/Lex/Lexer.h"
13 #include "clang/Lex/Preprocessor.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace modernize {
20 
21 namespace {
22 
23 constexpr char ConstructorCall[] = "constructorCall";
24 constexpr char ResetCall[] = "resetCall";
25 constexpr char NewExpression[] = "newExpression";
26 
27 std::string getNewExprName(const CXXNewExpr *NewExpr, const SourceManager &SM,
28  const LangOptions &Lang) {
29  StringRef WrittenName = Lexer::getSourceText(
30  CharSourceRange::getTokenRange(
31  NewExpr->getAllocatedTypeSourceInfo()->getTypeLoc().getSourceRange()),
32  SM, Lang);
33  if (NewExpr->isArray()) {
34  return (WrittenName + "[]").str();
35  }
36  return WrittenName.str();
37 }
38 
39 } // namespace
40 
41 const char MakeSmartPtrCheck::PointerType[] = "pointerType";
42 
43 MakeSmartPtrCheck::MakeSmartPtrCheck(StringRef Name, ClangTidyContext *Context,
44  StringRef MakeSmartPtrFunctionName)
45  : ClangTidyCheck(Name, Context),
46  Inserter(Options.getLocalOrGlobal("IncludeStyle",
47  utils::IncludeSorter::IS_LLVM)),
48  MakeSmartPtrFunctionHeader(
49  Options.get("MakeSmartPtrFunctionHeader", "<memory>")),
50  MakeSmartPtrFunctionName(
51  Options.get("MakeSmartPtrFunction", MakeSmartPtrFunctionName)),
52  IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)),
53  IgnoreDefaultInitialization(
54  Options.get("IgnoreDefaultInitialization", true)) {}
55 
57  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
58  Options.store(Opts, "MakeSmartPtrFunctionHeader", MakeSmartPtrFunctionHeader);
59  Options.store(Opts, "MakeSmartPtrFunction", MakeSmartPtrFunctionName);
60  Options.store(Opts, "IgnoreMacros", IgnoreMacros);
61  Options.store(Opts, "IgnoreDefaultInitialization",
62  IgnoreDefaultInitialization);
63 }
64 
66  const LangOptions &LangOpts) const {
67  return LangOpts.CPlusPlus11;
68 }
69 
70 void MakeSmartPtrCheck::registerPPCallbacks(const SourceManager &SM,
71  Preprocessor *PP,
72  Preprocessor *ModuleExpanderPP) {
73  Inserter.registerPreprocessor(PP);
74 }
75 
76 void MakeSmartPtrCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
77  // Calling make_smart_ptr from within a member function of a type with a
78  // private or protected constructor would be ill-formed.
79  auto CanCallCtor = unless(has(ignoringImpCasts(
80  cxxConstructExpr(hasDeclaration(decl(unless(isPublic())))))));
81 
82  auto IsPlacement = hasAnyPlacementArg(anything());
83 
84  Finder->addMatcher(
85  traverse(
86  TK_AsIs,
87  cxxBindTemporaryExpr(has(ignoringParenImpCasts(
88  cxxConstructExpr(
89  hasType(getSmartPointerTypeMatcher()), argumentCountIs(1),
90  hasArgument(
91  0, cxxNewExpr(hasType(pointsTo(qualType(hasCanonicalType(
92  equalsBoundNode(PointerType))))),
93  CanCallCtor, unless(IsPlacement))
94  .bind(NewExpression)),
95  unless(isInTemplateInstantiation()))
96  .bind(ConstructorCall))))),
97  this);
98 
99  Finder->addMatcher(
100  traverse(TK_AsIs,
101  cxxMemberCallExpr(
102  thisPointerType(getSmartPointerTypeMatcher()),
103  callee(cxxMethodDecl(hasName("reset"))),
104  hasArgument(0, cxxNewExpr(CanCallCtor, unless(IsPlacement))
105  .bind(NewExpression)),
106  unless(isInTemplateInstantiation()))
107  .bind(ResetCall)),
108  this);
109 }
110 
111 void MakeSmartPtrCheck::check(const MatchFinder::MatchResult &Result) {
112  // 'smart_ptr' refers to 'std::shared_ptr' or 'std::unique_ptr' or other
113  // pointer, 'make_smart_ptr' refers to 'std::make_shared' or
114  // 'std::make_unique' or other function that creates smart_ptr.
115 
116  SourceManager &SM = *Result.SourceManager;
117  const auto *Construct =
118  Result.Nodes.getNodeAs<CXXConstructExpr>(ConstructorCall);
119  const auto *Reset = Result.Nodes.getNodeAs<CXXMemberCallExpr>(ResetCall);
120  const auto *Type = Result.Nodes.getNodeAs<QualType>(PointerType);
121  const auto *New = Result.Nodes.getNodeAs<CXXNewExpr>(NewExpression);
122 
123  // Skip when this is a new-expression with `auto`, e.g. new auto(1)
124  if (New->getType()->getPointeeType()->getContainedAutoType())
125  return;
126 
127  // Be conservative for cases where we construct and default initialize.
128  //
129  // For example,
130  // P.reset(new int) // check fix: P = std::make_unique<int>()
131  // P.reset(new int[5]) // check fix: P = std::make_unique<int []>(5)
132  //
133  // The fix of the check has side effect, it introduces value initialization
134  // which maybe unexpected and cause performance regression.
135  bool Initializes = New->hasInitializer() ||
137  New->getAllocatedType(), *Result.Context);
138  if (!Initializes && IgnoreDefaultInitialization)
139  return;
140  if (Construct)
141  checkConstruct(SM, Result.Context, Construct, Type, New);
142  else if (Reset)
143  checkReset(SM, Result.Context, Reset, New);
144 }
145 
146 void MakeSmartPtrCheck::checkConstruct(SourceManager &SM, ASTContext *Ctx,
147  const CXXConstructExpr *Construct,
148  const QualType *Type,
149  const CXXNewExpr *New) {
150  SourceLocation ConstructCallStart = Construct->getExprLoc();
151  bool InMacro = ConstructCallStart.isMacroID();
152 
153  if (InMacro && IgnoreMacros) {
154  return;
155  }
156 
157  bool Invalid = false;
158  StringRef ExprStr = Lexer::getSourceText(
159  CharSourceRange::getCharRange(
160  ConstructCallStart, Construct->getParenOrBraceRange().getBegin()),
161  SM, getLangOpts(), &Invalid);
162  if (Invalid)
163  return;
164 
165  auto Diag = diag(ConstructCallStart, "use %0 instead")
166  << MakeSmartPtrFunctionName;
167 
168  // Disable the fix in macros.
169  if (InMacro) {
170  return;
171  }
172 
173  if (!replaceNew(Diag, New, SM, Ctx)) {
174  return;
175  }
176 
177  // Find the location of the template's left angle.
178  size_t LAngle = ExprStr.find('<');
179  SourceLocation ConstructCallEnd;
180  if (LAngle == StringRef::npos) {
181  // If the template argument is missing (because it is part of the alias)
182  // we have to add it back.
183  ConstructCallEnd = ConstructCallStart.getLocWithOffset(ExprStr.size());
184  Diag << FixItHint::CreateInsertion(
185  ConstructCallEnd, "<" + getNewExprName(New, SM, getLangOpts()) + ">");
186  } else {
187  ConstructCallEnd = ConstructCallStart.getLocWithOffset(LAngle);
188  }
189 
190  Diag << FixItHint::CreateReplacement(
191  CharSourceRange::getCharRange(ConstructCallStart, ConstructCallEnd),
192  MakeSmartPtrFunctionName);
193 
194  // If the smart_ptr is built with brace enclosed direct initialization, use
195  // parenthesis instead.
196  if (Construct->isListInitialization()) {
197  SourceRange BraceRange = Construct->getParenOrBraceRange();
198  Diag << FixItHint::CreateReplacement(
199  CharSourceRange::getCharRange(
200  BraceRange.getBegin(), BraceRange.getBegin().getLocWithOffset(1)),
201  "(");
202  Diag << FixItHint::CreateReplacement(
203  CharSourceRange::getCharRange(BraceRange.getEnd(),
204  BraceRange.getEnd().getLocWithOffset(1)),
205  ")");
206  }
207 
208  insertHeader(Diag, SM.getFileID(ConstructCallStart));
209 }
210 
211 void MakeSmartPtrCheck::checkReset(SourceManager &SM, ASTContext *Ctx,
212  const CXXMemberCallExpr *Reset,
213  const CXXNewExpr *New) {
214  const auto *Expr = cast<MemberExpr>(Reset->getCallee());
215  SourceLocation OperatorLoc = Expr->getOperatorLoc();
216  SourceLocation ResetCallStart = Reset->getExprLoc();
217  SourceLocation ExprStart = Expr->getBeginLoc();
218  SourceLocation ExprEnd =
219  Lexer::getLocForEndOfToken(Expr->getEndLoc(), 0, SM, getLangOpts());
220 
221  bool InMacro = ExprStart.isMacroID();
222 
223  if (InMacro && IgnoreMacros) {
224  return;
225  }
226 
227  // There are some cases where we don't have operator ("." or "->") of the
228  // "reset" expression, e.g. call "reset()" method directly in the subclass of
229  // "std::unique_ptr<>". We skip these cases.
230  if (OperatorLoc.isInvalid()) {
231  return;
232  }
233 
234  auto Diag = diag(ResetCallStart, "use %0 instead")
235  << MakeSmartPtrFunctionName;
236 
237  // Disable the fix in macros.
238  if (InMacro) {
239  return;
240  }
241 
242  if (!replaceNew(Diag, New, SM, Ctx)) {
243  return;
244  }
245 
246  Diag << FixItHint::CreateReplacement(
247  CharSourceRange::getCharRange(OperatorLoc, ExprEnd),
248  (llvm::Twine(" = ") + MakeSmartPtrFunctionName + "<" +
249  getNewExprName(New, SM, getLangOpts()) + ">")
250  .str());
251 
252  if (Expr->isArrow())
253  Diag << FixItHint::CreateInsertion(ExprStart, "*");
254 
255  insertHeader(Diag, SM.getFileID(OperatorLoc));
256 }
257 
258 bool MakeSmartPtrCheck::replaceNew(DiagnosticBuilder &Diag,
259  const CXXNewExpr *New, SourceManager &SM,
260  ASTContext *Ctx) {
261  auto SkipParensParents = [&](const Expr *E) {
262  TraversalKindScope RAII(*Ctx, TK_AsIs);
263 
264  for (const Expr *OldE = nullptr; E != OldE;) {
265  OldE = E;
266  for (const auto &Node : Ctx->getParents(*E)) {
267  if (const Expr *Parent = Node.get<ParenExpr>()) {
268  E = Parent;
269  break;
270  }
271  }
272  }
273  return E;
274  };
275 
276  SourceRange NewRange = SkipParensParents(New)->getSourceRange();
277  SourceLocation NewStart = NewRange.getBegin();
278  SourceLocation NewEnd = NewRange.getEnd();
279 
280  // Skip when the source location of the new expression is invalid.
281  if (NewStart.isInvalid() || NewEnd.isInvalid())
282  return false;
283 
284  std::string ArraySizeExpr;
285  if (const auto* ArraySize = New->getArraySize().getValueOr(nullptr)) {
286  ArraySizeExpr = Lexer::getSourceText(CharSourceRange::getTokenRange(
287  ArraySize->getSourceRange()),
288  SM, getLangOpts())
289  .str();
290  }
291  // Returns true if the given constructor expression has any braced-init-list
292  // argument, e.g.
293  // Foo({1, 2}, 1) => true
294  // Foo(Bar{1, 2}) => true
295  // Foo(1) => false
296  // Foo{1} => false
297  auto HasListIntializedArgument = [](const CXXConstructExpr *CE) {
298  for (const auto *Arg : CE->arguments()) {
299  Arg = Arg->IgnoreImplicit();
300 
301  if (isa<CXXStdInitializerListExpr>(Arg) || isa<InitListExpr>(Arg))
302  return true;
303  // Check whether we implicitly construct a class from a
304  // std::initializer_list.
305  if (const auto *CEArg = dyn_cast<CXXConstructExpr>(Arg)) {
306  // Strip the elidable move constructor, it is present in the AST for
307  // C++11/14, e.g. Foo(Bar{1, 2}), the move constructor is around the
308  // init-list constructor.
309  if (CEArg->isElidable()) {
310  if (const auto *TempExp = CEArg->getArg(0)) {
311  if (const auto *UnwrappedCE =
312  dyn_cast<CXXConstructExpr>(TempExp->IgnoreImplicit()))
313  CEArg = UnwrappedCE;
314  }
315  }
316  if (CEArg->isStdInitListInitialization())
317  return true;
318  }
319  }
320  return false;
321  };
322  switch (New->getInitializationStyle()) {
323  case CXXNewExpr::NoInit: {
324  if (ArraySizeExpr.empty()) {
325  Diag << FixItHint::CreateRemoval(SourceRange(NewStart, NewEnd));
326  } else {
327  // New array expression without written initializer:
328  // smart_ptr<Foo[]>(new Foo[5]);
329  Diag << FixItHint::CreateReplacement(SourceRange(NewStart, NewEnd),
330  ArraySizeExpr);
331  }
332  break;
333  }
334  case CXXNewExpr::CallInit: {
335  // FIXME: Add fixes for constructors with parameters that can be created
336  // with a C++11 braced-init-list (e.g. std::vector, std::map).
337  // Unlike ordinal cases, braced list can not be deduced in
338  // std::make_smart_ptr, we need to specify the type explicitly in the fixes:
339  // struct S { S(std::initializer_list<int>, int); };
340  // struct S2 { S2(std::vector<int>); };
341  // struct S3 { S3(S2, int); };
342  // smart_ptr<S>(new S({1, 2, 3}, 1)); // C++98 call-style initialization
343  // smart_ptr<S>(new S({}, 1));
344  // smart_ptr<S2>(new S2({1})); // implicit conversion:
345  // // std::initializer_list => std::vector
346  // smart_ptr<S3>(new S3({1, 2}, 3));
347  // The above samples have to be replaced with:
348  // std::make_smart_ptr<S>(std::initializer_list<int>({1, 2, 3}), 1);
349  // std::make_smart_ptr<S>(std::initializer_list<int>({}), 1);
350  // std::make_smart_ptr<S2>(std::vector<int>({1}));
351  // std::make_smart_ptr<S3>(S2{1, 2}, 3);
352  if (const auto *CE = New->getConstructExpr()) {
353  if (HasListIntializedArgument(CE))
354  return false;
355  }
356  if (ArraySizeExpr.empty()) {
357  SourceRange InitRange = New->getDirectInitRange();
358  Diag << FixItHint::CreateRemoval(
359  SourceRange(NewStart, InitRange.getBegin()));
360  Diag << FixItHint::CreateRemoval(SourceRange(InitRange.getEnd(), NewEnd));
361  }
362  else {
363  // New array expression with default/value initialization:
364  // smart_ptr<Foo[]>(new int[5]());
365  // smart_ptr<Foo[]>(new Foo[5]());
366  Diag << FixItHint::CreateReplacement(SourceRange(NewStart, NewEnd),
367  ArraySizeExpr);
368  }
369  break;
370  }
371  case CXXNewExpr::ListInit: {
372  // Range of the substring that we do not want to remove.
373  SourceRange InitRange;
374  if (const auto *NewConstruct = New->getConstructExpr()) {
375  if (NewConstruct->isStdInitListInitialization() ||
376  HasListIntializedArgument(NewConstruct)) {
377  // FIXME: Add fixes for direct initialization with the initializer-list
378  // constructor. Similar to the above CallInit case, the type has to be
379  // specified explicitly in the fixes.
380  // struct S { S(std::initializer_list<int>); };
381  // struct S2 { S2(S, int); };
382  // smart_ptr<S>(new S{1, 2, 3}); // C++11 direct list-initialization
383  // smart_ptr<S>(new S{}); // use initializer-list constructor
384  // smart_ptr<S2>()new S2{ {1,2}, 3 }; // have a list-initialized arg
385  // The above cases have to be replaced with:
386  // std::make_smart_ptr<S>(std::initializer_list<int>({1, 2, 3}));
387  // std::make_smart_ptr<S>(std::initializer_list<int>({}));
388  // std::make_smart_ptr<S2>(S{1, 2}, 3);
389  return false;
390  }
391  // Direct initialization with ordinary constructors.
392  // struct S { S(int x); S(); };
393  // smart_ptr<S>(new S{5});
394  // smart_ptr<S>(new S{}); // use default constructor
395  // The arguments in the initialization list are going to be forwarded to
396  // the constructor, so this has to be replaced with:
397  // std::make_smart_ptr<S>(5);
398  // std::make_smart_ptr<S>();
399  InitRange = SourceRange(
400  NewConstruct->getParenOrBraceRange().getBegin().getLocWithOffset(1),
401  NewConstruct->getParenOrBraceRange().getEnd().getLocWithOffset(-1));
402  } else {
403  // Aggregate initialization.
404  // smart_ptr<Pair>(new Pair{first, second});
405  // Has to be replaced with:
406  // smart_ptr<Pair>(Pair{first, second});
407  //
408  // The fix (std::make_unique) needs to see copy/move constructor of
409  // Pair. If we found any invisible or deleted copy/move constructor, we
410  // stop generating fixes -- as the C++ rule is complicated and we are less
411  // certain about the correct fixes.
412  if (const CXXRecordDecl *RD = New->getType()->getPointeeCXXRecordDecl()) {
413  if (llvm::find_if(RD->ctors(), [](const CXXConstructorDecl *Ctor) {
414  return Ctor->isCopyOrMoveConstructor() &&
415  (Ctor->isDeleted() || Ctor->getAccess() == AS_private);
416  }) != RD->ctor_end()) {
417  return false;
418  }
419  }
420  InitRange = SourceRange(
421  New->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
422  New->getInitializer()->getSourceRange().getEnd());
423  }
424  Diag << FixItHint::CreateRemoval(
425  CharSourceRange::getCharRange(NewStart, InitRange.getBegin()));
426  Diag << FixItHint::CreateRemoval(
427  SourceRange(InitRange.getEnd().getLocWithOffset(1), NewEnd));
428  break;
429  }
430  }
431  return true;
432 }
433 
434 void MakeSmartPtrCheck::insertHeader(DiagnosticBuilder &Diag, FileID FD) {
435  if (MakeSmartPtrFunctionHeader.empty()) {
436  return;
437  }
438  Diag << Inserter.createIncludeInsertion(FD, MakeSmartPtrFunctionHeader);
439 }
440 
441 } // namespace modernize
442 } // namespace tidy
443 } // namespace clang
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Definition: ClangTidyOptions.h:115
clang::tidy::modernize::MakeSmartPtrCheck::registerPPCallbacks
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Override this to register PPCallbacks in the preprocessor.
Definition: MakeSmartPtrCheck.cpp:70
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Returns matcher that match with different smart pointer types.
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Registers this with the Preprocessor PP, must be called before this class is used.
Definition: IncludeInserter.cpp:42
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Definition: TUScheduler.cpp:460
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Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:54
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const LangOptions & getLangOpts() const
Returns the language options from the context.
Definition: ClangTidyCheck.h:420
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Returns true if Type is trivially default constructible.
Definition: TypeTraits.cpp:92
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Definition: AbseilMatcher.h:14
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Definition: ClangTidyCheck.h:416
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Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:72
clang::tidy::modernize::MakeSmartPtrCheck::storeOptions
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Definition: MakeSmartPtrCheck.cpp:56
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Definition: UppercaseLiteralSuffixCheck.cpp:28
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Add a diagnostic with the check's name.
Definition: ClangTidyCheck.cpp:25
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Returns whether the C++ version is compatible with current check.
Definition: MakeSmartPtrCheck.cpp:65
MakeSharedCheck.h
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Definition: Serialize.cpp:223
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Definition: MakeSmartPtrCheck.cpp:111
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Definition: AvoidBindCheck.cpp:67
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Definition: IncludeInserter.h:84
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===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
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Definition: IncludeInserter.cpp:70
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Definition: ClangTidyCheck.cpp:120
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Definition: MakeSmartPtrCheck.h:46
clang::tidy::modernize::MakeSmartPtrCheck::registerMatchers
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Override this to register AST matchers with Finder.
Definition: MakeSmartPtrCheck.cpp:76