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 TK_AsIs, binaryOperation(hasOperatorName("="), hasLHS(IsPartOfSource))
34 .bind(MutatingOperatorName));
35
36 const auto MemberExprOrSelf = anyOf(memberExpr(), cxxThisExpr());
37
38 const auto IsPartOfSelf = allOf(
39 unless(hasDescendant(expr(unless(MemberExprOrSelf)))), MemberExprOrSelf);
40
41 const auto IsSelfMutatingAssignment =
42 binaryOperation(isAssignmentOperator(), hasLHS(IsPartOfSelf));
43
44 const auto IsSelfMutatingMemberFunction =
45 functionDecl(hasBody(hasDescendant(IsSelfMutatingAssignment)));
46
47 const auto IsSourceMutatingMemberCall =
48 cxxMemberCallExpr(on(IsPartOfSource),
49 callee(IsSelfMutatingMemberFunction))
50 .bind(MutatingCallName);
51
52 const auto MutatesSource = allOf(
53 hasParameter(
54 0, parmVarDecl(hasType(lValueReferenceType())).bind(SourceDeclName)),
55 anyOf(forEachDescendant(IsSourceMutatingAssignment),
56 forEachDescendant(IsSourceMutatingMemberCall)));
57
58 Finder->addMatcher(cxxConstructorDecl(isCopyConstructor(), MutatesSource),
59 this);
60
61 Finder->addMatcher(cxxMethodDecl(isCopyAssignmentOperator(), MutatesSource),
62 this);
63 }
64
check(const MatchFinder::MatchResult & Result)65 void MutatingCopyCheck::check(const MatchFinder::MatchResult &Result) {
66 if (const auto *MemberCall =
67 Result.Nodes.getNodeAs<CXXMemberCallExpr>(MutatingCallName))
68 diag(MemberCall->getBeginLoc(), "call mutates copied object");
69 else if (const auto *Assignment =
70 Result.Nodes.getNodeAs<Expr>(MutatingOperatorName))
71 diag(Assignment->getBeginLoc(), "mutating copied object");
72 }
73
74 } // namespace cert
75 } // namespace tidy
76 } // namespace clang
77