clang-tools 10.0.0

UndelegatedConstructorCheck.cpp
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1 //===--- UndelegatedConstructorCheck.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 "UndelegatedConstructorCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/Lex/Lexer.h"
12
13 using namespace clang::ast_matchers;
14
15 namespace clang {
16 namespace tidy {
17 namespace bugprone {
18
19 namespace {
20 AST_MATCHER_P(Stmt, ignoringTemporaryExpr,
21 ast_matchers::internal::Matcher<Stmt>, InnerMatcher) {
22 const Stmt *E = &Node;
23 for (;;) {
24 // Temporaries with non-trivial dtors.
25 if (const auto *EWC = dyn_cast<ExprWithCleanups>(E))
26 E = EWC->getSubExpr();
27 // Temporaries with zero or more than two ctor arguments.
28 else if (const auto *BTE = dyn_cast<CXXBindTemporaryExpr>(E))
29 E = BTE->getSubExpr();
30 // Temporaries with exactly one ctor argument.
31 else if (const auto *FCE = dyn_cast<CXXFunctionalCastExpr>(E))
32 E = FCE->getSubExpr();
33 else
34 break;
35 }
36
37 return InnerMatcher.matches(*E, Finder, Builder);
38 }
39
40 // Finds a node if it's a base of an already bound node.
41 AST_MATCHER_P(CXXRecordDecl, baseOfBoundNode, std::string, ID) {
42 return Builder->removeBindings(
43 [&](const ast_matchers::internal::BoundNodesMap &Nodes) {
44 const auto *Derived = Nodes.getNodeAs<CXXRecordDecl>(ID);
45 return Derived != &Node && !Derived->isDerivedFrom(&Node);
46 });
47 }
48 } // namespace
49
50 void UndelegatedConstructorCheck::registerMatchers(MatchFinder *Finder) {
51 // We look for calls to constructors of the same type in constructors. To do
52 // this we have to look through a variety of nodes that occur in the path,
53 // depending on the type's destructor and the number of arguments on the
54 // constructor call, this is handled by ignoringTemporaryExpr. Ignore template
55 // instantiations to reduce the number of duplicated warnings.
56 //
57 // Only register the matchers for C++11; the functionality currently does not
58 // provide any benefit to other languages, despite being benign.
59 if (!getLangOpts().CPlusPlus11)
60 return;
61
62 Finder->addMatcher(
63 compoundStmt(
64 hasParent(
65 cxxConstructorDecl(ofClass(cxxRecordDecl().bind("parent")))),
66 forEach(ignoringTemporaryExpr(
67 cxxConstructExpr(hasDeclaration(cxxConstructorDecl(ofClass(
68 cxxRecordDecl(baseOfBoundNode("parent"))))))
69 .bind("construct"))),
70 unless(isInTemplateInstantiation())),
71 this);
72 }
73
74 void UndelegatedConstructorCheck::check(
75 const MatchFinder::MatchResult &Result) {
76 const auto *E = Result.Nodes.getNodeAs<CXXConstructExpr>("construct");
77 diag(E->getBeginLoc(), "did you intend to call a delegated constructor? "
78 "A temporary object is created here instead");
79 }
80
81 } // namespace bugprone
82 } // namespace tidy
83 } // namespace clang
clang::ast_matchers
Definition: AbseilMatcher.h:14
UndelegatedConstructorCheck.h
Builder
CodeCompletionBuilder Builder
Definition: CodeCompletionStringsTests.cpp:35
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
E
const Expr * E
Definition: AvoidBindCheck.cpp:82
clang::tidy::readability::AST_MATCHER_P
AST_MATCHER_P(CXXMethodDecl, hasCanonicalDecl, ast_matchers::internal::Matcher< CXXMethodDecl >, InnerMatcher)
Definition: ConvertMemberFunctionsToStatic.cpp:52