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 =
24 anyOf(hasType(pointerType()),
25 hasType(autoType(
26 hasDeducedType(hasUnqualifiedDesugaredType(pointerType())))),
27 hasType(decltypeType(hasUnderlyingType(pointerType()))));
28
29 // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
30 Finder->addMatcher(
31 binaryOperator(
32 hasAnyOperatorName("+", "-", "+=", "-="), AllPointerTypes,
33 unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
34 .bind("expr"),
35 this);
36
37 Finder->addMatcher(
38 unaryOperator(hasAnyOperatorName("++", "--"), hasType(pointerType()))
39 .bind("expr"),
40 this);
41
42 // Array subscript on a pointer (not an array) is also pointer arithmetic
43 Finder->addMatcher(
44 arraySubscriptExpr(
45 hasBase(ignoringImpCasts(
46 anyOf(AllPointerTypes,
47 hasType(decayedType(hasDecayedType(pointerType())))))))
48 .bind("expr"),
49 this);
50 }
51
check(const MatchFinder::MatchResult & Result)52 void ProBoundsPointerArithmeticCheck::check(
53 const MatchFinder::MatchResult &Result) {
54 const auto *MatchedExpr = Result.Nodes.getNodeAs<Expr>("expr");
55
56 diag(MatchedExpr->getExprLoc(), "do not use pointer arithmetic");
57 }
58
59 } // namespace cppcoreguidelines
60 } // namespace tidy
61 } // namespace clang
62