1 | //===--- DontModifyStdNamespaceCheck.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 "DontModifyStdNamespaceCheck.h" |
10 | #include "clang/ASTMatchers/ASTMatchFinder.h" |
11 | #include "clang/ASTMatchers/ASTMatchersInternal.h" |
12 | |
13 | using namespace clang; |
14 | using namespace clang::ast_matchers; |
15 | |
16 | namespace { |
17 | |
18 | AST_POLYMORPHIC_MATCHER_P( |
19 | hasAnyTemplateArgumentIncludingPack, |
20 | AST_POLYMORPHIC_SUPPORTED_TYPES(ClassTemplateSpecializationDecl, |
21 | TemplateSpecializationType, FunctionDecl), |
22 | clang::ast_matchers::internal::Matcher<TemplateArgument>, InnerMatcher) { |
23 | ArrayRef<TemplateArgument> Args = |
24 | clang::ast_matchers::internal::getTemplateSpecializationArgs(Node); |
25 | for (const auto &Arg : Args) { |
26 | if (Arg.getKind() != TemplateArgument::Pack) |
27 | continue; |
28 | ArrayRef<TemplateArgument> PackArgs = Arg.getPackAsArray(); |
29 | if (matchesFirstInRange(Matcher: InnerMatcher, Start: PackArgs.begin(), End: PackArgs.end(), |
30 | Finder, Builder) != PackArgs.end()) |
31 | return true; |
32 | } |
33 | return matchesFirstInRange(Matcher: InnerMatcher, Start: Args.begin(), End: Args.end(), Finder, |
34 | Builder) != Args.end(); |
35 | } |
36 | |
37 | } // namespace |
38 | |
39 | namespace clang::tidy::cert { |
40 | |
41 | void DontModifyStdNamespaceCheck::registerMatchers(MatchFinder *Finder) { |
42 | auto HasStdParent = |
43 | hasDeclContext(InnerMatcher: namespaceDecl(hasAnyName("std" , "posix" ), |
44 | unless(hasParent(namespaceDecl()))) |
45 | .bind(ID: "nmspc" )); |
46 | auto UserDefinedType = qualType( |
47 | hasUnqualifiedDesugaredType(InnerMatcher: tagType(unless(hasDeclaration(InnerMatcher: tagDecl( |
48 | hasAncestor(namespaceDecl(hasAnyName("std" , "posix" ), |
49 | unless(hasParent(namespaceDecl())))))))))); |
50 | auto HasNoProgramDefinedTemplateArgument = unless( |
51 | hasAnyTemplateArgumentIncludingPack(InnerMatcher: refersToType(InnerMatcher: UserDefinedType))); |
52 | auto InsideStdClassOrClassTemplateSpecialization = hasDeclContext( |
53 | InnerMatcher: anyOf(cxxRecordDecl(HasStdParent), |
54 | classTemplateSpecializationDecl( |
55 | HasStdParent, HasNoProgramDefinedTemplateArgument))); |
56 | |
57 | // Try to follow exactly CERT rule DCL58-CPP (this text is taken from C++ |
58 | // standard into the CERT rule): |
59 | // " |
60 | // 1 The behavior of a C++ program is undefined if it adds declarations or |
61 | // definitions to namespace std or to a namespace within namespace std unless |
62 | // otherwise specified. A program may add a template specialization for any |
63 | // standard library template to namespace std only if the declaration depends |
64 | // on a user-defined type and the specialization meets the standard library |
65 | // requirements for the original template and is not explicitly prohibited. 2 |
66 | // The behavior of a C++ program is undefined if it declares — an explicit |
67 | // specialization of any member function of a standard library class template, |
68 | // or — an explicit specialization of any member function template of a |
69 | // standard library class or class template, or — an explicit or partial |
70 | // specialization of any member class template of a standard library class or |
71 | // class template. |
72 | // " |
73 | // The "standard library requirements" and explicit prohibition are not |
74 | // checked. |
75 | |
76 | auto BadNonTemplateSpecializationDecl = |
77 | decl(unless(anyOf(functionDecl(isExplicitTemplateSpecialization()), |
78 | varDecl(isExplicitTemplateSpecialization()), |
79 | cxxRecordDecl(isExplicitTemplateSpecialization()))), |
80 | HasStdParent); |
81 | auto BadClassTemplateSpec = classTemplateSpecializationDecl( |
82 | HasNoProgramDefinedTemplateArgument, HasStdParent); |
83 | auto BadInnerClassTemplateSpec = classTemplateSpecializationDecl( |
84 | InsideStdClassOrClassTemplateSpecialization); |
85 | auto BadFunctionTemplateSpec = |
86 | functionDecl(unless(cxxMethodDecl()), isExplicitTemplateSpecialization(), |
87 | HasNoProgramDefinedTemplateArgument, HasStdParent); |
88 | auto BadMemberFunctionSpec = |
89 | cxxMethodDecl(isExplicitTemplateSpecialization(), |
90 | InsideStdClassOrClassTemplateSpecialization); |
91 | |
92 | Finder->addMatcher(NodeMatch: decl(anyOf(BadNonTemplateSpecializationDecl, |
93 | BadClassTemplateSpec, BadInnerClassTemplateSpec, |
94 | BadFunctionTemplateSpec, BadMemberFunctionSpec), |
95 | unless(isExpansionInSystemHeader())) |
96 | .bind(ID: "decl" ), |
97 | Action: this); |
98 | } |
99 | } // namespace clang::tidy::cert |
100 | |
101 | static const NamespaceDecl *getTopLevelLexicalNamespaceDecl(const Decl *D) { |
102 | const NamespaceDecl *LastNS = nullptr; |
103 | while (D) { |
104 | if (const auto *NS = dyn_cast<NamespaceDecl>(Val: D)) |
105 | LastNS = NS; |
106 | D = dyn_cast_or_null<Decl>(Val: D->getLexicalDeclContext()); |
107 | } |
108 | return LastNS; |
109 | } |
110 | |
111 | void clang::tidy::cert::DontModifyStdNamespaceCheck::check( |
112 | const MatchFinder::MatchResult &Result) { |
113 | const auto *D = Result.Nodes.getNodeAs<Decl>(ID: "decl" ); |
114 | const auto *NS = Result.Nodes.getNodeAs<NamespaceDecl>(ID: "nmspc" ); |
115 | if (!D || !NS) |
116 | return; |
117 | |
118 | diag(Loc: D->getLocation(), |
119 | Description: "modification of %0 namespace can result in undefined behavior" ) |
120 | << NS; |
121 | // 'NS' is not always the namespace declaration that lexically contains 'D', |
122 | // try to find such a namespace. |
123 | if (const NamespaceDecl *LexNS = getTopLevelLexicalNamespaceDecl(D)) { |
124 | assert(NS->getCanonicalDecl() == LexNS->getCanonicalDecl() && |
125 | "Mismatch in found namespace" ); |
126 | diag(LexNS->getLocation(), "%0 namespace opened here" , DiagnosticIDs::Note) |
127 | << LexNS; |
128 | } |
129 | } |
130 | |