clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsPointerArithmeticCheck.cpp

   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
  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
  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