1 //===-- StringCompareCheck.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 "StringCompareCheck.h"
10 #include "../utils/OptionsUtils.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/ASTMatchers/ASTMatchers.h"
14 #include "clang/Tooling/FixIt.h"
15 #include "llvm/ADT/StringRef.h"
16
17 using namespace clang::ast_matchers;
18 namespace optutils = clang::tidy::utils::options;
19
20 namespace clang::tidy::readability {
21
22 static const StringRef CompareMessage = "do not use 'compare' to test equality "
23 "of strings; use the string equality "
24 "operator instead";
25
26 static const StringRef DefaultStringLikeClasses = "::std::basic_string;"
27 "::std::basic_string_view";
28
StringCompareCheck(StringRef Name,ClangTidyContext * Context)29 StringCompareCheck::StringCompareCheck(StringRef Name,
30 ClangTidyContext *Context)
31 : ClangTidyCheck(Name, Context),
32 StringLikeClasses(optutils::parseStringList(
33 Options.get("StringLikeClasses", DefaultStringLikeClasses))) {}
34
storeOptions(ClangTidyOptions::OptionMap & Opts)35 void StringCompareCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
36 Options.store(Opts, "StringLikeClasses",
37 optutils::serializeStringList(StringLikeClasses));
38 }
39
registerMatchers(MatchFinder * Finder)40 void StringCompareCheck::registerMatchers(MatchFinder *Finder) {
41 if (StringLikeClasses.empty()) {
42 return;
43 }
44 const auto StrCompare = cxxMemberCallExpr(
45 callee(cxxMethodDecl(hasName("compare"), ofClass(cxxRecordDecl(hasAnyName(
46 StringLikeClasses))))),
47 hasArgument(0, expr().bind("str2")), argumentCountIs(1),
48 callee(memberExpr().bind("str1")));
49
50 // First and second case: cast str.compare(str) to boolean.
51 Finder->addMatcher(
52 traverse(TK_AsIs,
53 implicitCastExpr(hasImplicitDestinationType(booleanType()),
54 has(StrCompare))
55 .bind("match1")),
56 this);
57
58 // Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0.
59 Finder->addMatcher(
60 binaryOperator(hasAnyOperatorName("==", "!="),
61 hasOperands(StrCompare.bind("compare"),
62 integerLiteral(equals(0)).bind("zero")))
63 .bind("match2"),
64 this);
65 }
66
check(const MatchFinder::MatchResult & Result)67 void StringCompareCheck::check(const MatchFinder::MatchResult &Result) {
68 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match1")) {
69 diag(Matched->getBeginLoc(), CompareMessage);
70 return;
71 }
72
73 if (const auto *Matched = Result.Nodes.getNodeAs<Stmt>("match2")) {
74 const ASTContext &Ctx = *Result.Context;
75
76 if (const auto *Zero = Result.Nodes.getNodeAs<Stmt>("zero")) {
77 const auto *Str1 = Result.Nodes.getNodeAs<MemberExpr>("str1");
78 const auto *Str2 = Result.Nodes.getNodeAs<Stmt>("str2");
79 const auto *Compare = Result.Nodes.getNodeAs<Stmt>("compare");
80
81 auto Diag = diag(Matched->getBeginLoc(), CompareMessage);
82
83 if (Str1->isArrow())
84 Diag << FixItHint::CreateInsertion(Str1->getBeginLoc(), "*");
85
86 Diag << tooling::fixit::createReplacement(*Zero, *Str2, Ctx)
87 << tooling::fixit::createReplacement(*Compare, *Str1->getBase(),
88 Ctx);
89 }
90 }
91
92 // FIXME: Add fixit to fix the code for case one and two (match1).
93 }
94
95 } // namespace clang::tidy::readability
96