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 namespace cppcoreguidelines {
19 
20 void ProBoundsPointerArithmeticCheck::registerMatchers(MatchFinder *Finder) {
21   if (!getLangOpts().CPlusPlus)
22     return;
23 
24   // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
25   Finder->addMatcher(
26       binaryOperator(
27           anyOf(hasOperatorName("+"), hasOperatorName("-"),
28                 hasOperatorName("+="), hasOperatorName("-=")),
29           hasType(pointerType()),
30           unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
31           .bind("expr"),
32       this);
33 
34   Finder->addMatcher(
35       unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
36                     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(hasType(pointerType()),
45                     hasType(decayedType(hasDecayedType(pointerType())))))))
46           .bind("expr"),
47       this);
48 }
49 
50 void
51 ProBoundsPointerArithmeticCheck::check(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