1 //===--- AvoidConstOrRefDataMembersCheck.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 "AvoidConstOrRefDataMembersCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang::tidy::cppcoreguidelines {
16 
17 static bool isCopyConstructible(CXXRecordDecl const &Node) {
18   if (Node.needsOverloadResolutionForCopyConstructor() &&
19       Node.needsImplicitCopyConstructor()) {
20     // unresolved
21     for (CXXBaseSpecifier const &BS : Node.bases()) {
22       CXXRecordDecl const *BRD = BS.getType()->getAsCXXRecordDecl();
23       if (BRD != nullptr && !isCopyConstructible(*BRD))
24         return false;
25     }
26   }
27   if (Node.hasSimpleCopyConstructor())
28     return true;
29   for (CXXConstructorDecl const *Ctor : Node.ctors())
30     if (Ctor->isCopyConstructor())
31       return !Ctor->isDeleted();
32   return false;
33 }
34 
35 static bool isMoveConstructible(CXXRecordDecl const &Node) {
36   if (Node.needsOverloadResolutionForMoveConstructor() &&
37       Node.needsImplicitMoveConstructor()) {
38     // unresolved
39     for (CXXBaseSpecifier const &BS : Node.bases()) {
40       CXXRecordDecl const *BRD = BS.getType()->getAsCXXRecordDecl();
41       if (BRD != nullptr && !isMoveConstructible(*BRD))
42         return false;
43     }
44   }
45   if (Node.hasSimpleMoveConstructor())
46     return true;
47   for (CXXConstructorDecl const *Ctor : Node.ctors())
48     if (Ctor->isMoveConstructor())
49       return !Ctor->isDeleted();
50   return false;
51 }
52 
53 static bool isCopyAssignable(CXXRecordDecl const &Node) {
54   if (Node.needsOverloadResolutionForCopyAssignment() &&
55       Node.needsImplicitCopyAssignment()) {
56     // unresolved
57     for (CXXBaseSpecifier const &BS : Node.bases()) {
58       CXXRecordDecl const *BRD = BS.getType()->getAsCXXRecordDecl();
59       if (BRD != nullptr && !isCopyAssignable(*BRD))
60         return false;
61     }
62   }
63   if (Node.hasSimpleCopyAssignment())
64     return true;
65   for (CXXMethodDecl const *Method : Node.methods())
66     if (Method->isCopyAssignmentOperator())
67       return !Method->isDeleted();
68   return false;
69 }
70 
71 static bool isMoveAssignable(CXXRecordDecl const &Node) {
72   if (Node.needsOverloadResolutionForMoveAssignment() &&
73       Node.needsImplicitMoveAssignment()) {
74     // unresolved
75     for (CXXBaseSpecifier const &BS : Node.bases()) {
76       CXXRecordDecl const *BRD = BS.getType()->getAsCXXRecordDecl();
77       if (BRD != nullptr && !isMoveAssignable(*BRD))
78         return false;
79     }
80   }
81   if (Node.hasSimpleMoveAssignment())
82     return true;
83   for (CXXMethodDecl const *Method : Node.methods())
84     if (Method->isMoveAssignmentOperator())
85       return !Method->isDeleted();
86   return false;
87 }
88 
89 namespace {
90 
91 AST_MATCHER(FieldDecl, isMemberOfLambda) {
92   return Node.getParent()->isLambda();
93 }
94 
95 AST_MATCHER(CXXRecordDecl, isCopyableOrMovable) {
96   return isCopyConstructible(Node) || isMoveConstructible(Node) ||
97          isCopyAssignable(Node) || isMoveAssignable(Node);
98 }
99 
100 } // namespace
101 
102 void AvoidConstOrRefDataMembersCheck::registerMatchers(MatchFinder *Finder) {
103   Finder->addMatcher(
104       fieldDecl(
105           unless(isMemberOfLambda()),
106           anyOf(
107               fieldDecl(hasType(hasCanonicalType(referenceType()))).bind("ref"),
108               fieldDecl(hasType(qualType(isConstQualified()))).bind("const")),
109           hasDeclContext(cxxRecordDecl(isCopyableOrMovable()))),
110       this);
111 }
112 
113 void AvoidConstOrRefDataMembersCheck::check(
114     const MatchFinder::MatchResult &Result) {
115   if (const auto *MatchedDecl = Result.Nodes.getNodeAs<FieldDecl>("ref"))
116     diag(MatchedDecl->getLocation(), "member %0 of type %1 is a reference")
117         << MatchedDecl << MatchedDecl->getType();
118   if (const auto *MatchedDecl = Result.Nodes.getNodeAs<FieldDecl>("const"))
119     diag(MatchedDecl->getLocation(), "member %0 of type %1 is const qualified")
120         << MatchedDecl << MatchedDecl->getType();
121 }
122 
123 } // namespace clang::tidy::cppcoreguidelines
124