clang-tools 10.0.0

UnhandledSelfAssignmentCheck.cpp
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1 //===--- UnhandledSelfAssignmentCheck.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 "UnhandledSelfAssignmentCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12
13 using namespace clang::ast_matchers;
14
15 namespace clang {
16 namespace tidy {
17 namespace bugprone {
18
19 UnhandledSelfAssignmentCheck::UnhandledSelfAssignmentCheck(
20 StringRef Name, ClangTidyContext *Context)
21 : ClangTidyCheck(Name, Context),
22 WarnOnlyIfThisHasSuspiciousField(
23 Options.get("WarnOnlyIfThisHasSuspiciousField", true)) {}
24
25 void UnhandledSelfAssignmentCheck::storeOptions(
26 ClangTidyOptions::OptionMap &Opts) {
27 Options.store(Opts, "WarnOnlyIfThisHasSuspiciousField",
28 WarnOnlyIfThisHasSuspiciousField);
29 }
30
31 void UnhandledSelfAssignmentCheck::registerMatchers(MatchFinder *Finder) {
32 if (!getLangOpts().CPlusPlus)
33 return;
34
35 // We don't care about deleted, default or implicit operator implementations.
36 const auto IsUserDefined = cxxMethodDecl(
37 isDefinition(), unless(anyOf(isDeleted(), isImplicit(), isDefaulted())));
38
39 // We don't need to worry when a copy assignment operator gets the other
40 // object by value.
41 const auto HasReferenceParam =
42 cxxMethodDecl(hasParameter(0, parmVarDecl(hasType(referenceType()))));
43
44 // Self-check: Code compares something with 'this' pointer. We don't check
45 // whether it is actually the parameter what we compare.
46 const auto HasNoSelfCheck = cxxMethodDecl(unless(hasDescendant(
47 binaryOperator(anyOf(hasOperatorName("=="), hasOperatorName("!=")),
48 has(ignoringParenCasts(cxxThisExpr()))))));
49
50 // Both copy-and-swap and copy-and-move method creates a copy first and
51 // assign it to 'this' with swap or move.
52 // In the non-template case, we can search for the copy constructor call.
53 const auto HasNonTemplateSelfCopy = cxxMethodDecl(
54 ofClass(cxxRecordDecl(unless(hasAncestor(classTemplateDecl())))),
55 hasDescendant(cxxConstructExpr(hasDeclaration(cxxConstructorDecl(
56 isCopyConstructor(), ofClass(equalsBoundNode("class")))))));
57
58 // In the template case, we need to handle two separate cases: 1) a local
59 // variable is created with the copy, 2) copy is created only as a temporary
60 // object.
61 const auto HasTemplateSelfCopy = cxxMethodDecl(
62 ofClass(cxxRecordDecl(hasAncestor(classTemplateDecl()))),
63 anyOf(hasDescendant(
64 varDecl(hasType(cxxRecordDecl(equalsBoundNode("class"))),
65 hasDescendant(parenListExpr()))),
66 hasDescendant(cxxUnresolvedConstructExpr(hasDescendant(declRefExpr(
67 hasType(cxxRecordDecl(equalsBoundNode("class")))))))));
68
69 // If inside the copy assignment operator another assignment operator is
70 // called on 'this' we assume that self-check might be handled inside
71 // this nested operator.
72 const auto HasNoNestedSelfAssign =
73 cxxMethodDecl(unless(hasDescendant(cxxMemberCallExpr(callee(cxxMethodDecl(
74 hasName("operator="), ofClass(equalsBoundNode("class"))))))));
75
76 DeclarationMatcher AdditionalMatcher = cxxMethodDecl();
77 if (WarnOnlyIfThisHasSuspiciousField) {
78 // Matcher for standard smart pointers.
79 const auto SmartPointerType = qualType(hasUnqualifiedDesugaredType(
80 recordType(hasDeclaration(classTemplateSpecializationDecl(
81 hasAnyName("::std::shared_ptr", "::std::unique_ptr",
82 "::std::weak_ptr", "::std::auto_ptr"),
83 templateArgumentCountIs(1))))));
84
85 // We will warn only if the class has a pointer or a C array field which
86 // probably causes a problem during self-assignment (e.g. first resetting
87 // the pointer member, then trying to access the object pointed by the
88 // pointer, or memcpy overlapping arrays).
89 AdditionalMatcher = cxxMethodDecl(ofClass(cxxRecordDecl(
90 has(fieldDecl(anyOf(hasType(pointerType()), hasType(SmartPointerType),
91 hasType(arrayType())))))));
92 }
93
94 Finder->addMatcher(cxxMethodDecl(ofClass(cxxRecordDecl().bind("class")),
95 isCopyAssignmentOperator(), IsUserDefined,
96 HasReferenceParam, HasNoSelfCheck,
97 unless(HasNonTemplateSelfCopy),
98 unless(HasTemplateSelfCopy),
99 HasNoNestedSelfAssign, AdditionalMatcher)
100 .bind("copyAssignmentOperator"),
101 this);
102 }
103
104 void UnhandledSelfAssignmentCheck::check(
105 const MatchFinder::MatchResult &Result) {
106 const auto *MatchedDecl =
107 Result.Nodes.getNodeAs<CXXMethodDecl>("copyAssignmentOperator");
108 diag(MatchedDecl->getLocation(),
109 "operator=() does not handle self-assignment properly");
110 }
111
112 } // namespace bugprone
113 } // namespace tidy
114 } // namespace clang
clang::tidy::bugprone::UnhandledSelfAssignmentCheck::storeOptions
void storeOptions(ClangTidyOptions::OptionMap &Opts) override
Should store all options supported by this check with their current values or default values for opti...
Definition: UnhandledSelfAssignmentCheck.cpp:25
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang::tidy::bugprone::UnhandledSelfAssignmentCheck::check
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Definition: UnhandledSelfAssignmentCheck.cpp:104
clang::tidy::bugprone::UnhandledSelfAssignmentCheck::registerMatchers
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.
Definition: UnhandledSelfAssignmentCheck.cpp:31
clang::tidy::ClangTidyCheck
Base class for all clang-tidy checks.
Definition: ClangTidyCheck.h:47
clang::tidy::ClangTidyCheck::getLangOpts
const LangOptions & getLangOpts() const
Returns the language options from the context.
Definition: ClangTidyCheck.h:188
clang::tidy::ClangTidyCheck::Options
OptionsView Options
Definition: ClangTidyCheck.h:184
clang::tidy::ClangTidyCheck::OptionsView::store
void store(ClangTidyOptions::OptionMap &Options, StringRef LocalName, StringRef Value) const
Stores an option with the check-local name LocalName with string value Value to Options.
Definition: ClangTidyCheck.cpp:58
Name
static constexpr llvm::StringLiteral Name
Definition: UppercaseLiteralSuffixCheck.cpp:27
clang::tidy::ClangTidyOptions::OptionMap
std::map< std::string, std::string > OptionMap
Definition: ClangTidyOptions.h:97
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
clang::tidy::ClangTidyContext
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
Definition: ClangTidyDiagnosticConsumer.h:77
UnhandledSelfAssignmentCheck.h
clang::tidy::ClangTidyCheck::diag
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
Definition: ClangTidyCheck.cpp:21