clang-tools 20.0.0git
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
10#include "clang/AST/ASTContext.h"
11#include "clang/Lex/Lexer.h"
12
13using namespace clang::ast_matchers;
14
15namespace clang::tidy::bugprone {
16
17namespace {
18AST_MATCHER_P(Stmt, ignoringTemporaryExpr,
19 ast_matchers::internal::Matcher<Stmt>, InnerMatcher) {
20 const Stmt *E = &Node;
21 for (;;) {
22 // Temporaries with non-trivial dtors.
23 if (const auto *EWC = dyn_cast<ExprWithCleanups>(E))
24 E = EWC->getSubExpr();
25 // Temporaries with zero or more than two ctor arguments.
26 else if (const auto *BTE = dyn_cast<CXXBindTemporaryExpr>(E))
27 E = BTE->getSubExpr();
28 // Temporaries with exactly one ctor argument.
29 else if (const auto *FCE = dyn_cast<CXXFunctionalCastExpr>(E))
30 E = FCE->getSubExpr();
31 else
32 break;
33 }
34
35 return InnerMatcher.matches(*E, Finder, Builder);
36}
37
38// Finds a node if it's a base of an already bound node.
39AST_MATCHER_P(CXXRecordDecl, baseOfBoundNode, std::string, ID) {
40 return Builder->removeBindings(
41 [&](const ast_matchers::internal::BoundNodesMap &Nodes) {
42 const auto *Derived = Nodes.getNodeAs<CXXRecordDecl>(ID);
43 return Derived != &Node && !Derived->isDerivedFrom(&Node);
44 });
45}
46} // namespace
47
49 // We look for calls to constructors of the same type in constructors. To do
50 // this we have to look through a variety of nodes that occur in the path,
51 // depending on the type's destructor and the number of arguments on the
52 // constructor call, this is handled by ignoringTemporaryExpr. Ignore template
53 // instantiations to reduce the number of duplicated warnings.
54
55 Finder->addMatcher(
56 traverse(
57 TK_AsIs,
58 compoundStmt(hasParent(cxxConstructorDecl(
59 ofClass(cxxRecordDecl().bind("parent")))),
60 forEach(ignoringTemporaryExpr(
61 cxxConstructExpr(
62 hasDeclaration(cxxConstructorDecl(ofClass(
63 cxxRecordDecl(baseOfBoundNode("parent"))))))
64 .bind("construct"))),
65 unless(isInTemplateInstantiation()))),
66 this);
67}
68
70 const MatchFinder::MatchResult &Result) {
71 const auto *E = Result.Nodes.getNodeAs<CXXConstructExpr>("construct");
72 diag(E->getBeginLoc(), "did you intend to call a delegated constructor? "
73 "A temporary object is created here instead");
74}
75
76} // namespace clang::tidy::bugprone
const Expr * E
CodeCompletionBuilder Builder
::clang::DynTypedNode Node
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check's name.
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
AST_MATCHER_P(FunctionDecl, parameterCountGE, unsigned, N)
Matches functions that have at least the specified amount of parameters.