1 //===--- ProBoundsPointerArithmeticCheck.cpp - clang-tidy------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "ProBoundsPointerArithmeticCheck.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 
14 using namespace clang::ast_matchers;
15 
16 namespace clang {
17 namespace tidy {
18 
19 void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
20   if (!getLangOpts().CPlusPlus)
21     return;
22 
23   // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
24   Finder->addMatcher(
25       binaryOperator(anyOf(hasOperatorName("+"), hasOperatorName("-"),
26                            hasOperatorName("+="), hasOperatorName("-=")),
27                      hasType(pointerType()))
28           .bind("expr"),
29       this);
30 
31   Finder->addMatcher(
32       unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
33                     hasType(pointerType()))
34           .bind("expr"),
35       this);
36 
37   // Array subscript on a pointer (not an array) is also pointer arithmetic
38   Finder->addMatcher(
39       arraySubscriptExpr(hasBase(ignoringImpCasts(anyOf(hasType(pointerType()),
40                                                         hasType(decayedType(hasDecayedType(pointerType())))))))
41           .bind("expr"),
42       this);
43 }
44 
45 void
46 ProBoundsPointerArithmeticCheck::check(const MatchFinder::MatchResult &Result) {
47   const auto *MatchedExpr = Result.Nodes.getNodeAs<Expr>("expr");
48 
49   diag(MatchedExpr->getExprLoc(), "do not use pointer arithmetic");
50 }
51 
52 } // namespace tidy
53 } // namespace clang
54