clang-tools 10.0.0

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