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::tidy::cert {
16
17 static constexpr llvm::StringLiteral SourceDeclName = "ChangedPVD";
18 static constexpr llvm::StringLiteral MutatingOperatorName = "MutatingOp";
19 static constexpr llvm::StringLiteral MutatingCallName = "MutatingCall";
20
registerMatchers(MatchFinder * Finder)21 void MutatingCopyCheck::registerMatchers(MatchFinder *Finder) {
22 const auto MemberExprOrSourceObject = anyOf(
23 memberExpr(),
24 declRefExpr(to(decl(equalsBoundNode(std::string(SourceDeclName))))));
25
26 const auto IsPartOfSource =
27 allOf(unless(hasDescendant(expr(unless(MemberExprOrSourceObject)))),
28 MemberExprOrSourceObject);
29
30 const auto IsSourceMutatingAssignment = traverse(
31 TK_AsIs, binaryOperation(hasOperatorName("="), hasLHS(IsPartOfSource))
32 .bind(MutatingOperatorName));
33
34 const auto MemberExprOrSelf = anyOf(memberExpr(), cxxThisExpr());
35
36 const auto IsPartOfSelf = allOf(
37 unless(hasDescendant(expr(unless(MemberExprOrSelf)))), MemberExprOrSelf);
38
39 const auto IsSelfMutatingAssignment =
40 binaryOperation(isAssignmentOperator(), hasLHS(IsPartOfSelf));
41
42 const auto IsSelfMutatingMemberFunction =
43 functionDecl(hasBody(hasDescendant(IsSelfMutatingAssignment)));
44
45 const auto IsSourceMutatingMemberCall =
46 cxxMemberCallExpr(on(IsPartOfSource),
47 callee(IsSelfMutatingMemberFunction))
48 .bind(MutatingCallName);
49
50 const auto MutatesSource = allOf(
51 hasParameter(
52 0, parmVarDecl(hasType(lValueReferenceType())).bind(SourceDeclName)),
53 anyOf(forEachDescendant(IsSourceMutatingAssignment),
54 forEachDescendant(IsSourceMutatingMemberCall)));
55
56 Finder->addMatcher(cxxConstructorDecl(isCopyConstructor(), MutatesSource),
57 this);
58
59 Finder->addMatcher(cxxMethodDecl(isCopyAssignmentOperator(), MutatesSource),
60 this);
61 }
62
check(const MatchFinder::MatchResult & Result)63 void MutatingCopyCheck::check(const MatchFinder::MatchResult &Result) {
64 if (const auto *MemberCall =
65 Result.Nodes.getNodeAs<CXXMemberCallExpr>(MutatingCallName))
66 diag(MemberCall->getBeginLoc(), "call mutates copied object");
67 else if (const auto *Assignment =
68 Result.Nodes.getNodeAs<Expr>(MutatingOperatorName))
69 diag(Assignment->getBeginLoc(), "mutating copied object");
70 }
71
72 } // namespace clang::tidy::cert
73