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 | |
13 | using namespace clang::ast_matchers; |
14 | |
15 | namespace clang::tidy::bugprone { |
16 | |
17 | static unsigned getPointerLevel(const QualType &PtrType) { |
18 | if (!PtrType->isPointerType()) |
19 | return 0U; |
20 | |
21 | return 1U + getPointerLevel(PtrType: PtrType->castAs<PointerType>()->getPointeeType()); |
22 | } |
23 | |
24 | namespace { |
25 | |
26 | AST_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 | |
51 | AST_MATCHER(QualType, isPointerType) { |
52 | const QualType Type = |
53 | Node.getCanonicalType().getNonReferenceType().getUnqualifiedType(); |
54 | |
55 | return !Type.isNull() && Type->isPointerType(); |
56 | } |
57 | |
58 | } // namespace |
59 | |
60 | MultiLevelImplicitPointerConversionCheck:: |
61 | MultiLevelImplicitPointerConversionCheck(StringRef Name, |
62 | ClangTidyContext *Context) |
63 | : ClangTidyCheck(Name, Context), EnableInC(Options.get(LocalName: "EnableInC" , Default: true)) { |
64 | } |
65 | |
66 | void MultiLevelImplicitPointerConversionCheck::storeOptions( |
67 | ClangTidyOptions::OptionMap &Opts) { |
68 | Options.store(Options&: Opts, LocalName: "EnableInC" , Value: EnableInC); |
69 | } |
70 | |
71 | void 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 | |
81 | std::optional<TraversalKind> |
82 | MultiLevelImplicitPointerConversionCheck::getCheckTraversalKind() const { |
83 | return TK_AsIs; |
84 | } |
85 | |
86 | void 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 | |