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 auto *MatchedDecl = Result.Nodes.getNodeAs<CXXRecordDecl>("class-def");
86   if (!MatchedDecl)
87     return;
88 
89   ClassDefId ID(MatchedDecl->getLocation(), MatchedDecl->getName());
90 
91   std::initializer_list<std::pair<std::string, SpecialMemberFunctionKind>>
92       Matchers = {{"dtor", SpecialMemberFunctionKind::Destructor},
93                   {"copy-ctor", SpecialMemberFunctionKind::CopyConstructor},
94                   {"copy-assign", SpecialMemberFunctionKind::CopyAssignment},
95                   {"move-ctor", SpecialMemberFunctionKind::MoveConstructor},
96                   {"move-assign", SpecialMemberFunctionKind::MoveAssignment}};
97 
98   for (const auto &KV : Matchers)
99     if (Result.Nodes.getNodeAs<CXXMethodDecl>(KV.first)) {
100       SpecialMemberFunctionKind Kind = KV.second;
101       llvm::SmallVectorImpl<SpecialMemberFunctionKind> &Members =
102           ClassWithSpecialMembers[ID];
103       if (find(Members, Kind) == Members.end())
104         Members.push_back(Kind);
105     }
106 }
107 
108 void SpecialMemberFunctionsCheck::onEndOfTranslationUnit() {
109   llvm::SmallVector<SpecialMemberFunctionKind, 5> AllSpecialMembers = {
110       SpecialMemberFunctionKind::Destructor,
111       SpecialMemberFunctionKind::CopyConstructor,
112       SpecialMemberFunctionKind::CopyAssignment};
113 
114   if (getLangOpts().CPlusPlus11) {
115     AllSpecialMembers.push_back(SpecialMemberFunctionKind::MoveConstructor);
116     AllSpecialMembers.push_back(SpecialMemberFunctionKind::MoveAssignment);
117   }
118 
119   for (const auto &C : ClassWithSpecialMembers) {
120     const auto &DefinedSpecialMembers = C.second;
121 
122     if (DefinedSpecialMembers.size() == AllSpecialMembers.size())
123       continue;
124 
125     llvm::SmallVector<SpecialMemberFunctionKind, 5> UndefinedSpecialMembers;
126     std::set_difference(AllSpecialMembers.begin(), AllSpecialMembers.end(),
127                         DefinedSpecialMembers.begin(),
128                         DefinedSpecialMembers.end(),
129                         std::back_inserter(UndefinedSpecialMembers));
130 
131     diag(C.first.first, "class '%0' defines %1 but does not define %2")
132         << C.first.second << join(DefinedSpecialMembers, " and ")
133         << join(UndefinedSpecialMembers, " or ");
134   }
135 }
136 } // namespace cppcoreguidelines
137 } // namespace tidy
138 } // namespace clang
139