1 //===--- MutatingCopyCheck.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 "MutatingCopyCheck.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 cert {
18
19 static constexpr llvm::StringLiteral SourceDeclName = "ChangedPVD";
20 static constexpr llvm::StringLiteral MutatingOperatorName = "MutatingOp";
21 static constexpr llvm::StringLiteral MutatingCallName = "MutatingCall";
22
registerMatchers(MatchFinder * Finder)23 void MutatingCopyCheck::registerMatchers(MatchFinder *Finder) {
24 const auto MemberExprOrSourceObject = anyOf(
25 memberExpr(),
26 declRefExpr(to(decl(equalsBoundNode(std::string(SourceDeclName))))));
27
28 const auto IsPartOfSource =
29 allOf(unless(hasDescendant(expr(unless(MemberExprOrSourceObject)))),
30 MemberExprOrSourceObject);
31
32 const auto IsSourceMutatingAssignment = traverse(
33 ast_type_traits::TK_AsIs,
34 expr(anyOf(binaryOperator(isAssignmentOperator(), hasLHS(IsPartOfSource))
35 .bind(MutatingOperatorName),
36 cxxOperatorCallExpr(isAssignmentOperator(),
37 hasArgument(0, IsPartOfSource))
38 .bind(MutatingOperatorName))));
39
40 const auto MemberExprOrSelf = anyOf(memberExpr(), cxxThisExpr());
41
42 const auto IsPartOfSelf = allOf(
43 unless(hasDescendant(expr(unless(MemberExprOrSelf)))), MemberExprOrSelf);
44
45 const auto IsSelfMutatingAssignment =
46 expr(anyOf(binaryOperator(isAssignmentOperator(), hasLHS(IsPartOfSelf)),
47 cxxOperatorCallExpr(isAssignmentOperator(),
48 hasArgument(0, IsPartOfSelf))));
49
50 const auto IsSelfMutatingMemberFunction =
51 functionDecl(hasBody(hasDescendant(IsSelfMutatingAssignment)));
52
53 const auto IsSourceMutatingMemberCall =
54 cxxMemberCallExpr(on(IsPartOfSource),
55 callee(IsSelfMutatingMemberFunction))
56 .bind(MutatingCallName);
57
58 const auto MutatesSource = allOf(
59 hasParameter(
60 0, parmVarDecl(hasType(lValueReferenceType())).bind(SourceDeclName)),
61 anyOf(forEachDescendant(IsSourceMutatingAssignment),
62 forEachDescendant(IsSourceMutatingMemberCall)));
63
64 Finder->addMatcher(cxxConstructorDecl(isCopyConstructor(), MutatesSource),
65 this);
66
67 Finder->addMatcher(cxxMethodDecl(isCopyAssignmentOperator(), MutatesSource),
68 this);
69 }
70
check(const MatchFinder::MatchResult & Result)71 void MutatingCopyCheck::check(const MatchFinder::MatchResult &Result) {
72 if (const auto *MemberCall =
73 Result.Nodes.getNodeAs<CXXMemberCallExpr>(MutatingCallName))
74 diag(MemberCall->getBeginLoc(), "call mutates copied object");
75 else if (const auto *Assignment =
76 Result.Nodes.getNodeAs<Expr>(MutatingOperatorName))
77 diag(Assignment->getBeginLoc(), "mutating copied object");
78 }
79
80 } // namespace cert
81 } // namespace tidy
82 } // namespace clang
83