clang-tools  14.0.0git
CopyConstructorInitCheck.cpp
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1 //===--- CopyConstructorInitCheck.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 "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 namespace bugprone {
19 
20 void CopyConstructorInitCheck::registerMatchers(MatchFinder *Finder) {
21  // In the future this might be extended to move constructors?
22  Finder->addMatcher(
23  cxxConstructorDecl(
24  isCopyConstructor(),
25  hasAnyConstructorInitializer(cxxCtorInitializer(
26  isBaseInitializer(),
27  withInitializer(cxxConstructExpr(hasDeclaration(
28  cxxConstructorDecl(isDefaultConstructor())))))),
29  unless(isInstantiated()))
30  .bind("ctor"),
31  this);
32 }
33 
34 void CopyConstructorInitCheck::check(const MatchFinder::MatchResult &Result) {
35  const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
36  std::string ParamName = Ctor->getParamDecl(0)->getNameAsString();
37 
38  // We want only one warning (and FixIt) for each ctor.
39  std::string FixItInitList;
40  bool HasRelevantBaseInit = false;
41  bool ShouldNotDoFixit = false;
42  bool HasWrittenInitializer = false;
43  SmallVector<FixItHint, 2> SafeFixIts;
44  for (const auto *Init : Ctor->inits()) {
45  bool CtorInitIsWritten = Init->isWritten();
46  HasWrittenInitializer = HasWrittenInitializer || CtorInitIsWritten;
47  if (!Init->isBaseInitializer())
48  continue;
49  const Type *BaseType = Init->getBaseClass();
50  // Do not do fixits if there is a type alias involved or one of the bases
51  // are explicitly initialized. In the latter case we not do fixits to avoid
52  // -Wreorder warnings.
53  if (const auto *TempSpecTy = dyn_cast<TemplateSpecializationType>(BaseType))
54  ShouldNotDoFixit = ShouldNotDoFixit || TempSpecTy->isTypeAlias();
55  ShouldNotDoFixit = ShouldNotDoFixit || isa<TypedefType>(BaseType);
56  ShouldNotDoFixit = ShouldNotDoFixit || CtorInitIsWritten;
57  const CXXRecordDecl *BaseClass =
58  BaseType->getAsCXXRecordDecl()->getDefinition();
59  if (BaseClass->field_empty() &&
60  BaseClass->forallBases(
61  [](const CXXRecordDecl *Class) { return Class->field_empty(); }))
62  continue;
63  bool NonCopyableBase = false;
64  for (const auto *Ctor : BaseClass->ctors()) {
65  if (Ctor->isCopyConstructor() &&
66  (Ctor->getAccess() == AS_private || Ctor->isDeleted())) {
67  NonCopyableBase = true;
68  break;
69  }
70  }
71  if (NonCopyableBase)
72  continue;
73  const auto *CExpr = dyn_cast<CXXConstructExpr>(Init->getInit());
74  if (!CExpr || !CExpr->getConstructor()->isDefaultConstructor())
75  continue;
76  HasRelevantBaseInit = true;
77  if (CtorInitIsWritten) {
78  if (!ParamName.empty())
79  SafeFixIts.push_back(
80  FixItHint::CreateInsertion(CExpr->getEndLoc(), ParamName));
81  } else {
82  if (Init->getSourceLocation().isMacroID() ||
83  Ctor->getLocation().isMacroID() || ShouldNotDoFixit)
84  break;
85  FixItInitList += BaseClass->getNameAsString();
86  FixItInitList += "(" + ParamName + "), ";
87  }
88  }
89  if (!HasRelevantBaseInit)
90  return;
91 
92  auto Diag = diag(Ctor->getLocation(),
93  "calling a base constructor other than the copy constructor")
94  << SafeFixIts;
95 
96  if (FixItInitList.empty() || ParamName.empty() || ShouldNotDoFixit)
97  return;
98 
99  std::string FixItMsg{FixItInitList.substr(0, FixItInitList.size() - 2)};
100  SourceLocation FixItLoc;
101  // There is no initialization list in this constructor.
102  if (!HasWrittenInitializer) {
103  FixItLoc = Ctor->getBody()->getBeginLoc();
104  FixItMsg = " : " + FixItMsg;
105  } else {
106  // We apply the missing ctors at the beginning of the initialization list.
107  FixItLoc = (*Ctor->init_begin())->getSourceLocation();
108  FixItMsg += ',';
109  }
110  FixItMsg += ' ';
111 
112  Diag << FixItHint::CreateInsertion(FixItLoc, FixItMsg);
113 }
114 
115 } // namespace bugprone
116 } // namespace tidy
117 } // namespace clang
Type
NodeType Type
Definition: HTMLGenerator.cpp:73
clang::ast_matchers
Definition: AbseilMatcher.h:14
CopyConstructorInitCheck.h
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:259
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27