clang-tools 6.0.0

CopyConstructorInitCheck.cpp
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1 //===--- CopyConstructorInitCheck.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 "CopyConstructorInitCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang {
18 namespace tidy {
19 namespace bugprone {
20
21 void CopyConstructorInitCheck::registerMatchers(MatchFinder *Finder) {
22 if (!getLangOpts().CPlusPlus)
23 return;
24
25 // In the future this might be extended to move constructors?
26 Finder->addMatcher(
27 cxxConstructorDecl(
28 isCopyConstructor(),
29 hasAnyConstructorInitializer(cxxCtorInitializer(
30 isBaseInitializer(),
31 withInitializer(cxxConstructExpr(hasDeclaration(
32 cxxConstructorDecl(isDefaultConstructor())))))),
33 unless(isInstantiated()))
34 .bind("ctor"),
35 this);
36 }
37
38 void CopyConstructorInitCheck::check(const MatchFinder::MatchResult &Result) {
39 const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
40 std::string ParamName = Ctor->getParamDecl(0)->getNameAsString();
41
42 // We want only one warning (and FixIt) for each ctor.
43 std::string FixItInitList;
44 bool HasRelevantBaseInit = false;
45 bool ShouldNotDoFixit = false;
46 bool HasWrittenInitializer = false;
47 SmallVector<FixItHint, 2> SafeFixIts;
48 for (const auto *Init : Ctor->inits()) {
49 bool CtorInitIsWritten = Init->isWritten();
50 HasWrittenInitializer = HasWrittenInitializer || CtorInitIsWritten;
51 if (!Init->isBaseInitializer())
52 continue;
53 const Type *BaseType = Init->getBaseClass();
54 // Do not do fixits if there is a type alias involved or one of the bases
55 // are explicitly initialized. In the latter case we not do fixits to avoid
56 // -Wreorder warnings.
57 if (const auto *TempSpecTy = dyn_cast<TemplateSpecializationType>(BaseType))
58 ShouldNotDoFixit = ShouldNotDoFixit || TempSpecTy->isTypeAlias();
59 ShouldNotDoFixit = ShouldNotDoFixit || isa<TypedefType>(BaseType);
60 ShouldNotDoFixit = ShouldNotDoFixit || CtorInitIsWritten;
61 const CXXRecordDecl *BaseClass =
62 BaseType->getAsCXXRecordDecl()->getDefinition();
63 if (BaseClass->field_empty() &&
64 BaseClass->forallBases(
65 [](const CXXRecordDecl *Class) { return Class->field_empty(); }))
66 continue;
67 bool NonCopyableBase = false;
68 for (const auto *Ctor : BaseClass->ctors()) {
69 if (Ctor->isCopyConstructor() &&
70 (Ctor->getAccess() == AS_private || Ctor->isDeleted())) {
71 NonCopyableBase = true;
72 break;
73 }
74 }
75 if (NonCopyableBase)
76 continue;
77 const auto *CExpr = dyn_cast<CXXConstructExpr>(Init->getInit());
78 if (!CExpr || !CExpr->getConstructor()->isDefaultConstructor())
79 continue;
80 HasRelevantBaseInit = true;
81 if (CtorInitIsWritten) {
82 if (!ParamName.empty())
83 SafeFixIts.push_back(
84 FixItHint::CreateInsertion(CExpr->getLocEnd(), ParamName));
85 } else {
86 if (Init->getSourceLocation().isMacroID() ||
87 Ctor->getLocation().isMacroID() || ShouldNotDoFixit)
88 break;
89 FixItInitList += BaseClass->getNameAsString();
90 FixItInitList += "(" + ParamName + "), ";
91 }
92 }
93 if (!HasRelevantBaseInit)
94 return;
95
96 auto Diag = diag(Ctor->getLocation(),
97 "calling a base constructor other than the copy constructor")
98 << SafeFixIts;
99
100 if (FixItInitList.empty() || ParamName.empty() || ShouldNotDoFixit)
101 return;
102
103 std::string FixItMsg{FixItInitList.substr(0, FixItInitList.size() - 2)};
104 SourceLocation FixItLoc;
105 // There is no initialization list in this constructor.
106 if (!HasWrittenInitializer) {
107 FixItLoc = Ctor->getBody()->getLocStart();
108 FixItMsg = " : " + FixItMsg;
109 } else {
110 // We apply the missing ctors at the beginning of the initialization list.
111 FixItLoc = (*Ctor->init_begin())->getSourceLocation();
112 FixItMsg += ',';
113 }
114 FixItMsg += ' ';
115
116 Diag << FixItHint::CreateInsertion(FixItLoc, FixItMsg);
117 } // namespace misc
118
119 } // namespace misc
120 } // namespace tidy
121 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
CopyConstructorInitCheck.h
clang
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