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::tidy::cppcoreguidelines {
16
registerMatchers(MatchFinder * Finder)17 void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
18 if (!getLangOpts().CPlusPlus)
19 return;
20
21 const auto AllPointerTypes =
22 anyOf(hasType(pointerType()),
23 hasType(autoType(
24 hasDeducedType(hasUnqualifiedDesugaredType(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 clang::tidy::cppcoreguidelines
58