xref: /llvm-project/clang-tools-extra/clang-tidy/cppcoreguidelines/SpecialMemberFunctionsCheck.cpp (revision 77ec263e6025155850f117c934ae11eceaba5f3a)
1 //===--- SpecialMemberFunctionsCheck.cpp - clang-tidy----------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "SpecialMemberFunctionsCheck.h"
11 
12 #include "clang/AST/ASTContext.h"
13 #include "clang/ASTMatchers/ASTMatchFinder.h"
14 #include "llvm/ADT/DenseMapInfo.h"
15 #include "llvm/ADT/StringExtras.h"
16 
17 #define DEBUG_TYPE "clang-tidy"
18 
19 using namespace clang::ast_matchers;
20 
21 namespace clang {
22 namespace tidy {
23 namespace cppcoreguidelines {
24 
25 void SpecialMemberFunctionsCheck::registerMatchers(MatchFinder *Finder) {
26   if (!getLangOpts().CPlusPlus)
27     return;
28   Finder->addMatcher(
29       cxxRecordDecl(
30           eachOf(
31               has(cxxDestructorDecl(unless(isImplicit())).bind("dtor")),
32               has(cxxConstructorDecl(isCopyConstructor(), unless(isImplicit()))
33                       .bind("copy-ctor")),
34               has(cxxMethodDecl(isCopyAssignmentOperator(),
35                                 unless(isImplicit()))
36                       .bind("copy-assign")),
37               has(cxxConstructorDecl(isMoveConstructor(), unless(isImplicit()))
38                       .bind("move-ctor")),
39               has(cxxMethodDecl(isMoveAssignmentOperator(),
40                                 unless(isImplicit()))
41                       .bind("move-assign"))))
42           .bind("class-def"),
43       this);
44 }
45 
46 static llvm::StringRef
47 toString(SpecialMemberFunctionsCheck::SpecialMemberFunctionKind K) {
48   switch (K) {
49   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::Destructor:
50     return "a destructor";
51   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::CopyConstructor:
52     return "a copy constructor";
53   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::CopyAssignment:
54     return "a copy assignment operator";
55   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::MoveConstructor:
56     return "a move constructor";
57   case SpecialMemberFunctionsCheck::SpecialMemberFunctionKind::MoveAssignment:
58     return "a move assignment operator";
59   }
60   llvm_unreachable("Unhandled SpecialMemberFunctionKind");
61 }
62 
63 static std::string
64 join(ArrayRef<SpecialMemberFunctionsCheck::SpecialMemberFunctionKind> SMFS,
65      llvm::StringRef AndOr) {
66 
67   assert(!SMFS.empty() &&
68          "List of defined or undefined members should never be empty.");
69   std::string Buffer;
70   llvm::raw_string_ostream Stream(Buffer);
71 
72   Stream << toString(SMFS[0]);
73   size_t LastIndex = SMFS.size() - 1;
74   for (size_t i = 1; i < LastIndex; ++i) {
75     Stream << ", " << toString(SMFS[i]);
76   }
77   if (LastIndex != 0) {
78     Stream << AndOr << toString(SMFS[LastIndex]);
79   }
80   return Stream.str();
81 }
82 
83 void SpecialMemberFunctionsCheck::check(
84     const MatchFinder::MatchResult &Result) {
85   const CXXRecordDecl *MatchedDecl =
86       Result.Nodes.getNodeAs<CXXRecordDecl>("class-def");
87   if (!MatchedDecl)
88     return;
89 
90   ClassDefId ID(MatchedDecl->getLocation(), MatchedDecl->getName());
91 
92   std::initializer_list<std::pair<std::string, SpecialMemberFunctionKind>>
93       Matchers = {{"dtor", SpecialMemberFunctionKind::Destructor},
94                   {"copy-ctor", SpecialMemberFunctionKind::CopyConstructor},
95                   {"copy-assign", SpecialMemberFunctionKind::CopyAssignment},
96                   {"move-ctor", SpecialMemberFunctionKind::MoveConstructor},
97                   {"move-assign", SpecialMemberFunctionKind::MoveAssignment}};
98 
99   for (const auto &KV : Matchers)
100     if (Result.Nodes.getNodeAs<CXXMethodDecl>(KV.first))
101       ClassWithSpecialMembers[ID].insert(KV.second);
102 }
103 
104 void SpecialMemberFunctionsCheck::onEndOfTranslationUnit() {
105   llvm::SmallVector<SpecialMemberFunctionKind, 5> AllSpecialMembers = {
106       SpecialMemberFunctionKind::Destructor,
107       SpecialMemberFunctionKind::CopyConstructor,
108       SpecialMemberFunctionKind::CopyAssignment};
109 
110   if (getLangOpts().CPlusPlus11) {
111     AllSpecialMembers.push_back(SpecialMemberFunctionKind::MoveConstructor);
112     AllSpecialMembers.push_back(SpecialMemberFunctionKind::MoveAssignment);
113   }
114 
115   for (const auto &C : ClassWithSpecialMembers) {
116     const auto &DefinedSpecialMembers = C.second;
117 
118     if (DefinedSpecialMembers.size() == AllSpecialMembers.size())
119       continue;
120 
121     llvm::SmallVector<SpecialMemberFunctionKind, 5> UndefinedSpecialMembers;
122     std::set_difference(AllSpecialMembers.begin(), AllSpecialMembers.end(),
123                         DefinedSpecialMembers.begin(),
124                         DefinedSpecialMembers.end(),
125                         std::back_inserter(UndefinedSpecialMembers));
126 
127     diag(C.first.first, "class '%0' defines %1 but does not define %2")
128         << C.first.second << join(DefinedSpecialMembers.getArrayRef(), " and ")
129         << join(UndefinedSpecialMembers, " or ");
130   }
131 }
132 } // namespace cppcoreguidelines
133 } // namespace tidy
134 } // namespace clang
135