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 {
18 namespace tidy {
19 namespace readability {
20
registerMatchers(MatchFinder * Finder)21 void MisplacedArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
22 Finder->addMatcher(
23 traverse(ast_type_traits::TK_AsIs,
24 arraySubscriptExpr(hasLHS(hasType(isInteger())),
25 hasRHS(hasType(isAnyPointer())))
26 .bind("expr")),
27 this);
28 }
29
check(const MatchFinder::MatchResult & Result)30 void MisplacedArrayIndexCheck::check(const MatchFinder::MatchResult &Result) {
31 const auto *ArraySubscriptE =
32 Result.Nodes.getNodeAs<ArraySubscriptExpr>("expr");
33
34 auto Diag = diag(ArraySubscriptE->getBeginLoc(), "confusing array subscript "
35 "expression, usually the "
36 "index is inside the []");
37
38 // Only try to fixit when LHS and RHS can be swapped directly without changing
39 // the logic.
40 const Expr *RHSE = ArraySubscriptE->getRHS()->IgnoreParenImpCasts();
41 if (!isa<StringLiteral>(RHSE) && !isa<DeclRefExpr>(RHSE) &&
42 !isa<MemberExpr>(RHSE))
43 return;
44
45 const StringRef LText = tooling::fixit::getText(
46 ArraySubscriptE->getLHS()->getSourceRange(), *Result.Context);
47 const StringRef RText = tooling::fixit::getText(
48 ArraySubscriptE->getRHS()->getSourceRange(), *Result.Context);
49
50 Diag << FixItHint::CreateReplacement(
51 ArraySubscriptE->getLHS()->getSourceRange(), RText);
52 Diag << FixItHint::CreateReplacement(
53 ArraySubscriptE->getRHS()->getSourceRange(), LText);
54 }
55
56 } // namespace readability
57 } // namespace tidy
58 } // namespace clang
59