1//===--- MultiLevelImplicitPointerConversionCheck.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 "MultiLevelImplicitPointerConversionCheck.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/ASTMatchers/ASTMatchFinder.h"
12
13using namespace clang::ast_matchers;
14
15namespace clang::tidy::bugprone {
16
17static unsigned getPointerLevel(const QualType &PtrType) {
18 if (!PtrType->isPointerType())
19 return 0U;
20
21 return 1U + getPointerLevel(PtrType: PtrType->castAs<PointerType>()->getPointeeType());
22}
23
24namespace {
25
26AST_MATCHER(ImplicitCastExpr, isMultiLevelPointerConversion) {
27 const QualType TargetType = Node.getType()
28 .getCanonicalType()
29 .getNonReferenceType()
30 .getUnqualifiedType();
31 const QualType SourceType = Node.getSubExpr()
32 ->getType()
33 .getCanonicalType()
34 .getNonReferenceType()
35 .getUnqualifiedType();
36
37 if (TargetType == SourceType)
38 return false;
39
40 const unsigned TargetPtrLevel = getPointerLevel(PtrType: TargetType);
41 if (0U == TargetPtrLevel)
42 return false;
43
44 const unsigned SourcePtrLevel = getPointerLevel(PtrType: SourceType);
45 if (0U == SourcePtrLevel)
46 return false;
47
48 return SourcePtrLevel != TargetPtrLevel;
49}
50
51AST_MATCHER(QualType, isPointerType) {
52 const QualType Type =
53 Node.getCanonicalType().getNonReferenceType().getUnqualifiedType();
54
55 return !Type.isNull() && Type->isPointerType();
56}
57
58} // namespace
59
60MultiLevelImplicitPointerConversionCheck::
61 MultiLevelImplicitPointerConversionCheck(StringRef Name,
62 ClangTidyContext *Context)
63 : ClangTidyCheck(Name, Context), EnableInC(Options.get(LocalName: "EnableInC", Default: true)) {
64}
65
66void MultiLevelImplicitPointerConversionCheck::storeOptions(
67 ClangTidyOptions::OptionMap &Opts) {
68 Options.store(Options&: Opts, LocalName: "EnableInC", Value: EnableInC);
69}
70
71void MultiLevelImplicitPointerConversionCheck::registerMatchers(
72 MatchFinder *Finder) {
73 Finder->addMatcher(
74 NodeMatch: implicitCastExpr(hasCastKind(Kind: CK_BitCast), isMultiLevelPointerConversion(),
75 unless(hasParent(explicitCastExpr(
76 hasDestinationType(InnerMatcher: isPointerType())))))
77 .bind(ID: "expr"),
78 Action: this);
79}
80
81std::optional<TraversalKind>
82MultiLevelImplicitPointerConversionCheck::getCheckTraversalKind() const {
83 return TK_AsIs;
84}
85
86void MultiLevelImplicitPointerConversionCheck::check(
87 const MatchFinder::MatchResult &Result) {
88 const auto *MatchedExpr = Result.Nodes.getNodeAs<ImplicitCastExpr>(ID: "expr");
89 QualType Target = MatchedExpr->getType().getDesugaredType(*Result.Context);
90 QualType Source =
91 MatchedExpr->getSubExpr()->getType().getDesugaredType(*Result.Context);
92
93 diag(MatchedExpr->getExprLoc(), "multilevel pointer conversion from %0 to "
94 "%1, please use explicit cast")
95 << Source << Target;
96}
97
98} // namespace clang::tidy::bugprone
99

source code of clang-tools-extra/clang-tidy/bugprone/MultiLevelImplicitPointerConversionCheck.cpp