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   const auto AllPointerTypes = anyOf(
25       hasType(pointerType()), hasType(autoType(hasDeducedType(pointerType()))),
26       hasType(decltypeType(hasUnderlyingType(pointerType()))));
27 
28   // Flag all operators +, -, +=, -=, ++, -- that result in a pointer
29   Finder->addMatcher(
30       binaryOperator(
31           anyOf(hasOperatorName("+"), hasOperatorName("-"),
32                 hasOperatorName("+="), hasOperatorName("-=")),
33           AllPointerTypes,
34           unless(hasLHS(ignoringImpCasts(declRefExpr(to(isImplicit()))))))
35           .bind("expr"),
36       this);
37 
38   Finder->addMatcher(
39       unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
40                     hasType(pointerType()))
41           .bind("expr"),
42       this);
43 
44   // Array subscript on a pointer (not an array) is also pointer arithmetic
45   Finder->addMatcher(
46       arraySubscriptExpr(
47           hasBase(ignoringImpCasts(
48               anyOf(AllPointerTypes,
49                     hasType(decayedType(hasDecayedType(pointerType())))))))
50           .bind("expr"),
51       this);
52 }
53 
54 void ProBoundsPointerArithmeticCheck::check(
55     const MatchFinder::MatchResult &Result) {
56   const auto *MatchedExpr = Result.Nodes.getNodeAs<Expr>("expr");
57 
58   diag(MatchedExpr->getExprLoc(), "do not use pointer arithmetic");
59 }
60 
61 } // namespace cppcoreguidelines
62 } // namespace tidy
63 } // namespace clang
64