1 //===--- ProBoundsPointerArithmeticCheck.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 "ProBoundsPointerArithmeticCheck.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 cppcoreguidelines {
18
registerMatchers(MatchFinder * Finder)19 void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
20 if (!getLangOpts().CPlusPlus)
21 return;
22
23 const auto AllPointerTypes = anyOf(
24 hasType(pointerType()), hasType(autoType(hasDeducedType(pointerType()))),
25 hasType(decltypeType(hasUnderlyingType(pointerType()))));
26
27 // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
28 Finder->addMatcher(
29 binaryOperator(
30 hasAnyOperatorName("+", "-", "+=", "-="), AllPointerTypes,
31 unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
32 .bind("expr"),
33 this);
34
35 Finder->addMatcher(
36 unaryOperator(hasAnyOperatorName("++", "--"), hasType(pointerType()))
37 .bind("expr"),
38 this);
39
40 // Array subscript on a pointer (not an array) is also pointer arithmetic
41 Finder->addMatcher(
42 arraySubscriptExpr(
43 hasBase(ignoringImpCasts(
44 anyOf(AllPointerTypes,
45 hasType(decayedType(hasDecayedType(pointerType())))))))
46 .bind("expr"),
47 this);
48 }
49
check(const MatchFinder::MatchResult & Result)50 void ProBoundsPointerArithmeticCheck::check(
51 const MatchFinder::MatchResult &Result) {
52 const auto *MatchedExpr = Result.Nodes.getNodeAs<Expr>("expr");
53
54 diag(MatchedExpr->getExprLoc(), "do not use pointer arithmetic");
55 }
56
57 } // namespace cppcoreguidelines
58 } // namespace tidy
59 } // namespace clang
60