1 //===--- PointerArithmeticOnPolymorphicObjectCheck.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 "PointerArithmeticOnPolymorphicObjectCheck.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::bugprone {
16
17 namespace {
AST_MATCHER(CXXRecordDecl,isAbstract)18 AST_MATCHER(CXXRecordDecl, isAbstract) { return Node.isAbstract(); }
AST_MATCHER(CXXRecordDecl,isPolymorphic)19 AST_MATCHER(CXXRecordDecl, isPolymorphic) { return Node.isPolymorphic(); }
20 } // namespace
21
22 PointerArithmeticOnPolymorphicObjectCheck::
PointerArithmeticOnPolymorphicObjectCheck(StringRef Name,ClangTidyContext * Context)23 PointerArithmeticOnPolymorphicObjectCheck(StringRef Name,
24 ClangTidyContext *Context)
25 : ClangTidyCheck(Name, Context),
26 IgnoreInheritedVirtualFunctions(
27 Options.get("IgnoreInheritedVirtualFunctions", false)) {}
28
storeOptions(ClangTidyOptions::OptionMap & Opts)29 void PointerArithmeticOnPolymorphicObjectCheck::storeOptions(
30 ClangTidyOptions::OptionMap &Opts) {
31 Options.store(Opts, "IgnoreInheritedVirtualFunctions",
32 IgnoreInheritedVirtualFunctions);
33 }
34
registerMatchers(MatchFinder * Finder)35 void PointerArithmeticOnPolymorphicObjectCheck::registerMatchers(
36 MatchFinder *Finder) {
37 const auto PolymorphicPointerExpr =
38 expr(hasType(hasCanonicalType(pointerType(pointee(hasCanonicalType(
39 hasDeclaration(cxxRecordDecl(unless(isFinal()), isPolymorphic())
40 .bind("pointee"))))))))
41 .bind("pointer");
42
43 const auto PointerExprWithVirtualMethod =
44 expr(hasType(hasCanonicalType(
45 pointerType(pointee(hasCanonicalType(hasDeclaration(
46 cxxRecordDecl(
47 unless(isFinal()),
48 anyOf(hasMethod(isVirtualAsWritten()), isAbstract()))
49 .bind("pointee"))))))))
50 .bind("pointer");
51
52 const auto SelectedPointerExpr = IgnoreInheritedVirtualFunctions
53 ? PointerExprWithVirtualMethod
54 : PolymorphicPointerExpr;
55
56 const auto ArraySubscript = arraySubscriptExpr(hasBase(SelectedPointerExpr));
57
58 const auto BinaryOperators =
59 binaryOperator(hasAnyOperatorName("+", "-", "+=", "-="),
60 hasEitherOperand(SelectedPointerExpr));
61
62 const auto UnaryOperators = unaryOperator(
63 hasAnyOperatorName("++", "--"), hasUnaryOperand(SelectedPointerExpr));
64
65 Finder->addMatcher(ArraySubscript, this);
66 Finder->addMatcher(BinaryOperators, this);
67 Finder->addMatcher(UnaryOperators, this);
68 }
69
check(const MatchFinder::MatchResult & Result)70 void PointerArithmeticOnPolymorphicObjectCheck::check(
71 const MatchFinder::MatchResult &Result) {
72 const auto *PointerExpr = Result.Nodes.getNodeAs<Expr>("pointer");
73 const auto *PointeeDecl = Result.Nodes.getNodeAs<CXXRecordDecl>("pointee");
74
75 diag(PointerExpr->getBeginLoc(),
76 "pointer arithmetic on polymorphic object of type %0 can result in "
77 "undefined behavior if the dynamic type differs from the pointer type")
78 << PointeeDecl << PointerExpr->getSourceRange();
79 }
80
81 } // namespace clang::tidy::bugprone
82