1 //===--- MisplacedArrayIndexCheck.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 "MisplacedArrayIndexCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13 #include "clang/Tooling/FixIt.h"
14
15 using namespace clang::ast_matchers;
16
17 namespace clang::tidy::readability {
18
registerMatchers(MatchFinder * Finder)19 void MisplacedArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
20 Finder->addMatcher(
21 traverse(TK_AsIs, arraySubscriptExpr(hasLHS(hasType(isInteger())),
22 hasRHS(hasType(isAnyPointer())))
23 .bind("expr")),
24 this);
25 }
26
check(const MatchFinder::MatchResult & Result)27 void MisplacedArrayIndexCheck::check(const MatchFinder::MatchResult &Result) {
28 const auto *ArraySubscriptE =
29 Result.Nodes.getNodeAs<ArraySubscriptExpr>("expr");
30
31 auto Diag = diag(ArraySubscriptE->getBeginLoc(), "confusing array subscript "
32 "expression, usually the "
33 "index is inside the []");
34
35 // Only try to fixit when LHS and RHS can be swapped directly without changing
36 // the logic.
37 const Expr *RHSE = ArraySubscriptE->getRHS()->IgnoreParenImpCasts();
38 if (!isa<StringLiteral>(RHSE) && !isa<DeclRefExpr>(RHSE) &&
39 !isa<MemberExpr>(RHSE))
40 return;
41
42 const StringRef LText = tooling::fixit::getText(
43 ArraySubscriptE->getLHS()->getSourceRange(), *Result.Context);
44 const StringRef RText = tooling::fixit::getText(
45 ArraySubscriptE->getRHS()->getSourceRange(), *Result.Context);
46
47 Diag << FixItHint::CreateReplacement(
48 ArraySubscriptE->getLHS()->getSourceRange(), RText);
49 Diag << FixItHint::CreateReplacement(
50 ArraySubscriptE->getRHS()->getSourceRange(), LText);
51 }
52
53 } // namespace clang::tidy::readability
54